UNITIL CORP - Annual Report: 2012 (Form 10-K)

Table of Contents

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-K

For the fiscal year ended December 31, 2012

OR

Commission file number 1-8858

UNITIL CORPORATION

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (603) 772-0775

Securities registered pursuant to Section 12(b) of the Act:

Securities registered pursuant to Section 12(g) of the Act: NONE

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.    Yes  ¨    No  x

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.    Yes  ¨    No  x

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  x    No  ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).    Yes  x    No  ¨

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendments to this Form 10-K  x

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer”, “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act.

Large accelerated filer  ¨      Accelerated filer  x      Non-accelerated filer  ¨      Smaller reporting company  ¨

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).    Yes  ¨    No  x

Based on the closing price of the registrant’s common stock on June 30, 2012, the aggregate market value of common stock held by non-affiliates of the registrant was $359,089,609.

The number of the registrant’s common shares outstanding was 13,780,921 as of January 25, 2013.

Documents Incorporated by Reference:

Portions of the Proxy Statement relating to the Annual Meeting of Shareholders to be held on April 18, 2013 are incorporated by reference into Part III of this Report

Table of Contents

UNITIL CORPORATION

FORM 10-K

For the Fiscal Year Ended December 31, 2012

Table of Contents

Table of Contents

CAUTIONARY STATEMENT

This report and the documents incorporated by reference into this report contain statements that constitute “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, Section 21E of the Securities Exchange Act of 1934, as amended, and the Private Securities Litigation Reform Act of 1995. All statements, other than statements of historical fact, included or incorporated by reference into this report, including, without limitation, statements regarding the financial position, business strategy and other plans and objectives for the Company’s future operations, are forward-looking statements.

These statements include declarations regarding the Company’s beliefs and current expectations. In some cases, forward-looking statements can be identified by terminology such as “may,” “will,” “should,” “expects,” “plans,” “anticipates,” “believes,” “estimates,” “predicts,” “potential” or “continue” or the negative of such terms or other comparable terminology. These forward-looking statements are subject to inherent risks and uncertainties in predicting future results and conditions that could cause the actual results to differ materially from those projected in these forward-looking statements. Some, but not all, of the risks and uncertainties include those described in Part I, Item 1A (Risk Factors) and the following:

i

Table of Contents

Many of these risks are beyond the Company’s control. Any forward-looking statements speak only as of the date of this report, and the Company undertakes no obligation to update any forward-looking statements to reflect events or circumstances after the date on which such statements are made or to reflect the occurrence of unanticipated events. New factors emerge from time to time, and it is not possible for the Company to predict all of these factors, nor can the Company assess the impact of any such factor on its business or the extent to which any factor, or combination of factors, may cause results to differ materially from those contained in any forward-looking statements.

ii

Table of Contents

PART I

UNITIL CORPORATION

In this Annual Report on Form 10-K, the “Company”, “Unitil”, “we”, and “our” refer to Unitil Corporation and its subsidiaries, unless the context requires otherwise. Unitil is a public utility holding company and was incorporated under the laws of the State of New Hampshire in 1984. The following companies are wholly-owned subsidiaries of Unitil:

Unitil and its subsidiaries are subject to regulation as a holding company system by the Federal Energy Regulatory Commission (FERC) under the Energy Policy Act of 2005.

Unitil’s principal business is the local distribution of electricity and natural gas to approximately 175,400 customers throughout its service territories in the states of New Hampshire, Massachusetts and Maine. Unitil is the parent company of three wholly-owned distribution utilities: i) Unitil Energy, which provides electric service in the southeastern seacoast and state capital regions of New Hampshire, including the capital city of Concord, ii) Fitchburg, which provides both electric and natural gas service in the greater Fitchburg area of north central Massachusetts, and iii) Northern Utilities, which provides natural gas service in southeastern New Hampshire and portions of southern and central Maine, including the city of Portland, which is the largest city in northern New England. In addition, Unitil is the parent company of Granite State, an interstate natural gas transmission pipeline company that provides interstate natural gas pipeline access and transportation services to Northern Utilities in its New Hampshire and Maine service territory. Together, Unitil’s three distribution utilities serve approximately 101,700 electric customers and 73,700 natural gas customers.

Unitil’s distribution utilities had an investment in Net Utility Plant of $601.2 million at December 31, 2012. Unitil’s total operating revenue was $353.1 million in 2012. Unitil’s operating revenue is substantially derived from regulated distribution utility operations.

A fifth utility subsidiary, Unitil Power, formerly functioned as the full requirements wholesale power supply provider for Unitil Energy, but currently has limited business and operating activities. In connection with the implementation of electric industry restructuring in New Hampshire, Unitil Power ceased being the wholesale supplier of Unitil Energy in 2003 and divested of substantially all of its long-term power supply contracts through the sale of the entitlements to the electricity associated with those contracts.

1

Table of Contents

Unitil also has three other wholly-owned non-utility subsidiaries: Unitil Service, Unitil Realty and Unitil Resources. Unitil Service provides, at cost, a variety of administrative and professional services, including regulatory, financial, accounting, human resources, engineering, operations, technology and energy supply management services on a centralized basis to its affiliated Unitil companies. Unitil Realty owns and manages the Company’s corporate office in Hampton, New Hampshire. Unitil Resources is the Company’s wholly-owned non-regulated subsidiary. Usource, Inc. and Usource L.L.C. (collectively, Usource) are indirect subsidiaries that are wholly-owned by Unitil Resources. Usource provides energy brokering and advisory services to a national client base of large commercial and industrial customers. For segment information, see Note 8 (Segment Information) to the Consolidated Financial Statements included in Part II, Item 8 (Financial Statements and Supplementary Data) of this report.

OPERATIONS

Natural Gas Operations

Unitil’s natural gas operations include gas distribution utility operations and interstate gas transmission pipeline operations, discussed below. Revenue from Unitil’s gas operations was $160.6 million for 2012, which represents about 45% of Unitil’s total operating revenue.

Natural Gas Distribution Utility Operations

Unitil’s natural gas distribution operations are conducted through two of the Company’s operating utilities, Northern Utilities and Fitchburg. The primary business of Unitil’s natural gas utility operations is the local distribution of natural gas to customers in its service territory in New Hampshire, Massachusetts and Maine. As a result of a restructuring of the gas utility industry in New Hampshire, Massachusetts and Maine, Fitchburg’s residential and C&I customers and Northern Utilities’ C&I customers have the opportunity to purchase their natural gas supplies from third-party energy supply vendors. Most customers, however, continue to purchase such supplies through Northern Utilities and Fitchburg under regulated rates and tariffs. Northern Utilities and Fitchburg purchase natural gas from unaffiliated wholesale suppliers and recover the actual costs of these supplies on a pass-through basis through reconciling rate mechanisms that are periodically adjusted.

Natural gas is supplied and distributed by Northern Utilities to approximately 58,300 customers in 44 New Hampshire and southern Maine communities, from Plaistow, New Hampshire in the south to the city of Portland, Maine and then extending to Lewiston-Auburn, Maine in the north. Northern Utilities has a diversified customer base both in Maine and New Hampshire. Commercial businesses include healthcare, education, government and retail. Northern Utilities’ industrial base includes manufacturers in the auto, housing, rubber, printing, textile, pharmaceutical, electronics, wire and food production industries as well as a military installation. Northern Utilities’ 2012 gas operating revenue was $124.0 million, of which approximately 39% was derived from residential firm sales and 61% from commercial/industrial firm sales.

Natural gas is supplied and distributed by Fitchburg to approximately 15,400 customers in the communities of Fitchburg, Lunenburg, Townsend, Ashby, Gardner and Westminster, all located in Massachusetts. Fitchburg’s industrial customers include paper manufacturing and paper products companies, rubber and plastics manufacturers, chemical products companies and printing, publishing and associated industries. Fitchburg’s 2012 gas operating revenue was $31.6 million, of which approximately 52% was derived from residential firm sales and 48% from commercial/industrial firm sales.

Gas Transmission Pipeline Operations

Granite State is an interstate natural gas transmission pipeline company, operating 86 miles of underground gas transmission pipeline primarily located in Maine and New Hampshire. Granite State provides Northern Utilities with interconnection to three major natural gas pipelines and access to North American pipeline supplies. Granite State had operating revenue of $5.0 million for 2012. Granite State derives its revenues principally from the transportation services provided to Northern Utilities and to third-party marketers.

2

Table of Contents

Electric Distribution Utility Operations

Unitil’s electric distribution operations are conducted through two of the Company’s utilities, Unitil Energy and Fitchburg. Revenue from Unitil’s electric utility operations was $187.0 million for 2012, which represents about 53% of Unitil’s total operating revenue.

The primary business of Unitil’s electric utility operations is the local distribution of electricity to customers in its service territory in New Hampshire and Massachusetts. As a result of electric industry restructuring in New Hampshire and Massachusetts, Unitil’s customers are free to contract for their supply of electricity with third-party suppliers. The distribution utilities continue to deliver that supply of electricity over their distribution systems. Both Unitil Energy and Fitchburg supply electricity to those customers who do not obtain their supply from third-party suppliers, with the approved costs associated with electricity supplied by the distribution utilities being recovered on a pass-through basis under periodically adjusted rates.

Unitil Energy distributes electricity to approximately 73,300 customers in New Hampshire in the capital city of Concord as well as parts of 12 surrounding towns and all or part of 18 towns in the southeastern and seacoast regions of New Hampshire, including the towns of Hampton, Exeter, Atkinson and Plaistow. Unitil Energy’s service territory consists of approximately 408 square miles. In addition, Unitil Energy’s service territory encompasses retail trading and recreation centers for the central and southeastern parts of the state and includes the Hampton Beach recreational area. These areas serve diversified commercial and industrial businesses, including manufacturing firms engaged in the production of electronic components, wire and plastics, healthcare and education. Unitil Energy’s 2012 electric operating revenue was $128.2 million, of which approximately 55% was derived from residential sales and 45% from C&I sales.

Fitchburg is engaged in the distribution of both electricity and natural gas in the greater Fitchburg area of north central Massachusetts. Fitchburg’s service territory encompasses approximately 170 square miles. Electricity is supplied and distributed by Fitchburg to approximately 28,400 customers in the communities of Fitchburg, Ashby, Townsend and Lunenburg. Fitchburg’s industrial customers include paper manufacturing and paper products companies, rubber and plastics manufacturers, chemical products companies and printing, publishing and associated industries and educational institutions. Fitchburg’s 2012 electric operating revenue was $58.8 million, of which approximately 53% was derived from residential sales and 47% from C&I sales.

Seasonality

The Company’s results of operations are expected to reflect the seasonal nature of the natural gas business. Annual gas revenues are substantially realized during the heating season as a result of higher sales of natural gas due to cold weather. Accordingly, the results of operations are historically most favorable in the first and fourth quarters. Fluctuations in seasonal weather conditions may have a significant effect on the result of operations. Sales of electricity are generally less sensitive to weather than natural gas sales, but may also be affected by the weather conditions in both the winter and summer seasons.

Unitil Energy, Fitchburg and Northern Utilities are not dependent on a single customer or a few customers for their electric and natural gas sales.

Non-Regulated and Other Non-Utility Operations

Unitil’s non-regulated operations are conducted through Usource, a subsidiary of Unitil Resources. Usource provides energy brokering and advisory services to a national client base of large commercial and industrial customers. Revenue from Unitil’s non-regulated operations was $5.5 million in 2012.

The results of Unitil’s other non-utility subsidiaries, Unitil Service and Unitil Realty, and the holding company, are included in the Company’s consolidated results of operations. The results of these non-utility operations are principally derived from income earned on short-term investments and real property owned for Unitil’s and its subsidiaries’ use and are reported, after intercompany eliminations, in Other segment

3

Table of Contents

income. For segment information, see Note 8 (Segment Information) to the Consolidated Financial Statements included in Part II, Item 8 (Financial Statements and Supplementary Data) of this report.

RATES AND REGULATION

Unitil is subject to comprehensive regulation by federal and state regulatory authorities. Unitil and its subsidiaries are subject to regulation as a holding company system by the FERC under the Energy Policy Act of 2005 with regard to certain bookkeeping, accounting and reporting requirements. Unitil’s utility operations related to wholesale and interstate energy business activities are also regulated by the FERC. Unitil’s distribution utilities are subject to regulation by the applicable state public utility commissions, with regard to their rates, issuance of securities and other accounting and operational matters: Unitil Energy is subject to regulation by the New Hampshire Public Utilities Commission (NHPUC); Fitchburg is subject to regulation by the Massachusetts Department of Public Utilities (MDPU); and Northern Utilities is regulated by the NHPUC and Maine Public Utilities Commission (MPUC). Granite State, Unitil’s interstate natural gas transmission pipeline, is subject to regulation by the FERC with regard to its rates and operations. Because Unitil’s primary operations are subject to rate regulation, the regulatory treatment of various matters could significantly affect the Company’s operations and financial position.

Unitil’s distribution utilities deliver electricity and/or natural gas to all customers in their service territory, at rates established under cost of service regulation. Under this regulatory structure, Unitil’s distribution utilities recover the cost of providing distribution service to their customers based on a historical test year, in addition to earning a return on their capital investment in utility assets. In addition, the Company’s distribution utilities and its natural gas transmission pipeline company may also recover certain base rate costs, including capital project spending and enhanced reliability and vegetation management programs, through annual step adjustments and cost tracker rate mechanisms.

As a result of a restructuring of the utility industry in New Hampshire, Massachusetts and Maine, Unitil’s customers, with the exception of Northern Utilities’ residential customers, have the opportunity to purchase their electricity or natural gas supplies from third-party energy supply vendors. Most customers, however, continue to purchase such supplies through the distribution utilities under regulated energy rates and tariffs. Unitil’s distribution utilities purchase electricity or natural gas from unaffiliated wholesale suppliers and recover the actual approved costs of these supplies on a pass-through basis, as well as certain costs associated with industry restructuring, through reconciling rate mechanisms that are periodically adjusted.

In 2011 and 2012, the Company completed base rate cases for: Unitil Energy; the electric and gas divisions of Fitchburg; the New Hampshire and Maine divisions of Northern Utilities; and Granite State. The completion of these rate cases resulted in increases in annual distribution revenues of: $10.2 million for Unitil Energy; $3.3 million and $3.7 million for the electric and gas divisions of Fitchburg, respectively; and $3.7 million and $8.7 million for the New Hampshire and Maine divisions, respectively, of Northern Utilities. Granite State received approval for an increase of $2.2 million in annual revenue. Additionally, in 2011 and 2012, the Company completed rate filings that resulted in increases in annual revenues, through step adjustments and cost tracker rate mechanisms, of: $1.5 million for Unitil Energy; $0.5 million for the electric division of Fitchburg; and $0.3 million for Granite State.

Also see Regulatory Matters in Part II, Item 7(Management’s Discussion and Analysis of Financial Condition and Results of Operations) and Note 5 (Commitments and Contingencies) to the accompanying Consolidated Financial Statements for additional information on rates and regulation.

NATURAL GAS SUPPLY

Unitil manages gas supply for customers served by Northern Utilities in Maine and New Hampshire as well as customers served by Fitchburg in Massachusetts.

Fitchburg’s residential and C&I business customers have the opportunity to purchase their natural gas supply from third-party gas supply vendors. Many large and some medium C&I customers purchase their supplies from third-party suppliers, while most of Fitchburg’s residential and small C&I customers continue to purchase their supplies at regulated rates from Fitchburg. Northern Utilities’ C&I customers have the

4

Table of Contents

opportunity to purchase their natural gas supply from third-party gas supply vendors, and third-party supply is prevalent among Northern Utilities’ larger C&I customers. Most small C&I customers, as well as all residential customers, purchase their gas supply from Northern Utilities under regulated rates and tariffs. The approved costs associated with the acquisition of such wholesale natural gas supplies for customers who do not contract with third-party suppliers are recovered on a pass-through basis through periodically adjusted rates and are included in Purchased Gas in the Consolidated Statements of Earnings.

Regulated Natural Gas Supply

Fitchburg purchases natural gas under contracts of one year or less, as well as from producers and marketers on the spot market. Fitchburg arranges for gas delivery to its system through its own long-term contracts with Tennessee Gas Pipeline, or in the case of liquefied natural gas (LNG) or liquefied propane gas (LPG), to truck supplies to storage facilities within Fitchburg’s service territory.

Fitchburg has available under firm contract 14,057 million British Thermal Units (MMbtu) per day of year-round and seasonal transportation and underground storage capacity to its distribution facilities. As a supplement to pipeline natural gas, Fitchburg owns a propane air gas plant and a LNG storage and vaporization facility. These plants are used principally during peak load periods to augment the supply of pipeline natural gas.

Northern Utilities purchases a majority of its natural gas from U.S. domestic and Canadian suppliers under contracts of one year or less, and on occasion from producers and marketers on the spot market. Northern Utilities arranges for gas delivery to its system through its own long-term contracts with various interstate pipeline and storage facilities, through peaking supply contracts delivered to its system, or in the case of LNG, to truck supplies to storage facilities within Northern Utilities’ service territory.

Northern Utilities has available under firm contract 100,000 MMbtu per day of year-round and seasonal transportation capacity to its distribution facilities, and 3.4 billion cubic feet (BCF) of underground storage. As a supplement to pipeline natural gas, Northern Utilities owns a LNG storage and vaporization facility. This plant is used principally during peak load periods to augment the supply of pipeline natural gas.

ELECTRIC POWER SUPPLY

The restructuring of the electric utility industry in New Hampshire required the divestiture of Unitil’s power supply arrangements and the procurement of replacement supplies, which provided the flexibility for migration of customers to and from utility energy service. Fitchburg, Unitil Energy, and Unitil Power each are members of the New England Power Pool (NEPOOL) and participate in the ISO New England, Inc. (ISO-NE) markets for the purpose of facilitating these wholesale electric power supply transactions, which are necessary to serve Unitil’s customers.

As a result of restructuring of the electric utility industry in Massachusetts and New Hampshire, Unitil’s customers in both New Hampshire and Massachusetts have the opportunity to purchase their electric supply from competitive third-party energy suppliers. As of December 2012, 75% of Unitil’s largest New Hampshire customers, representing 24% of total New Hampshire electric energy sales, and 90% of Unitil’s largest Massachusetts customers, representing 31% of total Massachusetts electric energy sales, are purchasing their electric power supply in the competitive market. However, most residential and small commercial customers continue to purchase their electric supply through Unitil’s distribution utilities under regulated energy rates and tariffs. We believe that the concentration of the competitive retail market on higher use customers has been a common experience throughout the New England electricity market.

Regulated Electric Power Supply

In order to provide regulated electric supply service to their customers, Unitil’s electric distribution utilities enter into load-following wholesale electric power supply contracts with various wholesale suppliers.

5

Table of Contents

Fitchburg has power supply contracts with various wholesale suppliers for the provision of Basic Service energy supply. MDPU policy dictates the pricing structure and duration of each of these contracts. Basic Service power supply contracts for residential, small and medium general service customers are acquired every six months, are 12 months in duration and provide 50% of the supply requirements. On June 13, 2012, the MDPU approved, for a period of one year, Fitchburg’s request to discontinue the procurement process for Fitchburg’s large customers and become the load-serving entity for these customers. Currently, all Basic Service power supply requirements for large accounts are assigned to Fitchburg’s ISO-NE settlement account where Fitchburg procures electric supply through ISO-NE’s real-time market.

Unitil Energy currently has power supply contracts with various wholesale suppliers for the provision of Default Service to its customers. On July 31, 2012, the NHPUC approved Unitil Energy’s request to modify its Default Service solicitation to a process where 100% of the Default Service requirements are acquired for six months. Unitil Energy is in the process of transitioning to this procurement strategy which will be completed in late 2013. Currently, Unitil Energy has a group of contracts of varying duration and percentage to meet its Default Service supply requirements.

The NHPUC and MDPU regularly review alternatives to their procurement policy, which may lead to future changes in this regulated power supply procurement structure.

Regional Electric Transmission and Power Markets

Fitchburg, Unitil Energy and Unitil Power, as well as virtually all New England electric utilities, are participants in the ISO-NE markets. ISO-NE is the Regional Transmission Organization (RTO) in New England. The purpose of ISO-NE is to assure reliable operation of the bulk power system in the most economical manner for the region. Substantially all operation and dispatching of electric generation and bulk transmission capacity in New England are performed on a regional basis. The ISO-NE tariff imposes generating capacity and reserve obligations, and provides for the use of major transmission facilities and support payments associated therewith. The most notable benefits of the ISO-NE are coordinated, reliable power system operation and a supportive business environment for the development of competitive electric markets.

Electric Power Supply Divestiture

In connection with the implementation of retail choice, Unitil Power, which formerly functioned as the wholesale power supply provider for Unitil Energy, and Fitchburg divested their long-term power supply contracts through the sale of the entitlements to the electricity sold under those contracts. Unitil Energy and Fitchburg recover in their rates all the costs associated with the divestiture of their power supply portfolios and have secured regulatory approval from the NHPUC and MDPU, respectively, for the recovery of power supply-related stranded costs and other restructuring-related regulatory assets. The companies have a continuing obligation to submit regulatory filings that demonstrate their compliance with regulatory mandates and provide for timely recovery of costs in accordance with their approved restructuring plans.

ENVIRONMENTAL MATTERS

The Company’s past and present operations include activities that are generally subject to extensive and complex federal and state environmental laws and regulations. The Company believes it is in compliance with applicable environmental and safety laws and regulations, and the Company believes that as of December 31, 2012, there were no material losses reasonably likely to be incurred in excess of recorded amounts. However, we cannot assure you that significant costs and liabilities will not be incurred in the future. It is possible that other developments, such as increasingly stringent federal, state or local environmental laws and regulations could result in increased environmental compliance costs.

Fitchburg’s Manufactured Gas Plant Site—Fitchburg continues to work with environmental regulatory agencies to identify and assess environmental issues at the former manufactured gas plant (MGP) site at Sawyer Passway, located in Fitchburg, Massachusetts. Fitchburg proceeded with site remediation work as specified on the Tier 1B permit issued by the Massachusetts Department of Environmental

6

Table of Contents

Protection, which allowed Fitchburg to achieve temporary closure of the site. A status of temporary closure requires Fitchburg to monitor the site until a feasible permanent remediation alternative can be developed and completed.

Fitchburg recovers the environmental response costs incurred at this former MGP site in gas rates pursuant to the terms of a cost recovery agreement approved by the MDPU. Pursuant to this agreement, Fitchburg is authorized to amortize and recover environmental response costs from gas customers over succeeding seven-year periods, without carrying costs. Fitchburg had filed suit against several of its former insurance carriers seeking coverage for past and future environmental response costs at the site. In January 2011, Fitchburg settled with the remaining insurance carriers for approximately $2.0 million and received these payments in the first quarter of 2011. Any recovery that Fitchburg receives from insurance or third-parties with respect to environmental response costs, net of the unrecovered costs associated therewith, are shared equally between Fitchburg and its gas customers.

Northern Utilities’ Manufactured Gas Plant Sites—Northern Utilities has an extensive program to identify, investigate and remediate former MGP sites that were operated from the mid-1800s through the mid-1900s. In New Hampshire, MGP sites were identified in Dover, Exeter, Portsmouth, Rochester and Somersworth. This program has also documented the presence of MGP sites in Lewiston and Portland, Maine and a former MGP disposal site in Scarborough, Maine. Northern Utilities has worked with the environmental regulatory agencies in both New Hampshire and Maine to address environmental concerns with these sites.

Northern Utilities or others have substantially completed remediation of the Exeter, Rochester, Somersworth, Portsmouth, and Scarborough sites. The sites in Lewiston and Portland have been investigated and remedial activities are currently underway. Additionally, Northern Utilities has entered into a Letter of Intent with an unrelated third-party to redevelop the Portland site as a boat repair facility and to reduce and offset site remediation costs. Future operation, maintenance and remedial costs have been accrued, although there will be uncertainty regarding future costs until all remedial activities are completed.

The NHPUC and MPUC have approved the recovery of MGP environmental costs. For Northern Utilities’ New Hampshire division, the NHPUC approved the recovery of MGP environmental costs over a seven-year amortization period. For Northern Utilities’ Maine division, the MPUC authorized the recovery of environmental remediation costs over a rolling five-year amortization schedule.

Also, see Environmental Matters in Part II, Item 7 (Management’s Discussion and Analysis of Financial Condition and Results of Operations) and Note 5 (Commitments and Contingencies) to the accompanying Consolidated Financial Statements for additional information on Environmental Matters.

EMPLOYEES

As of December 31, 2012, the Company and its subsidiaries had 467 employees. The Company considers its relationship with employees to be good and has not experienced any major labor disruptions.

As of December 31, 2012, 157 of the Company’s employees were represented by labor unions. There are 78 union employees covered by two separate collective bargaining agreements which expire on May 31, 2013 and June 5, 2014. The agreements provide discrete salary adjustments, established work practices and uniform benefit packages. The Company expects to negotiate new agreements prior to their expiration dates.

There are 35 union employees who are covered by a separate collective bargaining agreement which expires on March 31, 2017. The agreement includes discrete salary adjustments, established work practices and uniform benefit packages.

There are 39 union employees who are covered by a separate collective bargaining agreement which expires on May 31, 2018. The agreement includes discrete salary adjustments, established work practices and uniform benefit packages.

In October 2012, the Electric Systems Operators, which is a group of five employees, voted to be represented by a union. The terms have not yet been negotiated for a new collective bargaining agreement covering this group of five employees.

7

Table of Contents

AVAILABLE INFORMATION

The Internet address for the Company’s website is www.unitil.com. On its website, the Company makes available, free of charge, its Securities and Exchange Commission (SEC) fillings, including annual reports on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K and other reports, as well as amendments to those reports. These reports are made available through the Investors section of Unitil’s website via a direct link to the section of the SEC’s website which contains Unitil’s SEC filings.

The Company’s current Code of Ethics was approved by Unitil’s Board of Directors on January 15, 2004. This Code of Ethics, along with any amendments or waivers, is also available on Unitil’s website.

Unitil’s common stock is listed on the New York Stock Exchange under the ticker symbol “UTL”.

DIRECTORS AND EXECUTIVE OFFICERS OF THE REGISTRANT

The following table provides information about our directors and executive officers as of January 30, 2013:

Robert G. Schoenberger has been Unitil’s Chairman of the Board of Directors and Chief Executive Officer since October 1997, and his current term will expire in 2015. Mr. Schoenberger has also served as Unitil’s President since 2003. Prior to his employment with Unitil, Mr. Schoenberger was president and chief operating officer of the New York Power Authority (a state-owned utility) from 1993 until 1997. Mr. Schoenberger has also served as a director of Satcon Technology Corporation, Boston, Massachusetts (a company that develops innovative power conversion solutions for the renewable power industry) since 2007. Mr. Schoenberger has also served as chairman and trustee of Exeter Health Resources, Exeter, New Hampshire, from 2012 to present, as well as from 1998 until 2009. Mr. Schoenberger also serves as a Director of the Edison Electric Institute, and as chairman of the Tocqueville Society of the Greater Seacoast (New Hampshire) United Way.

Mark H. Collin has been Unitil’s Senior Vice President and Chief Financial Officer since February 2003. Mr. Collin has also served as Treasurer since 1998. Mr. Collin joined Unitil in 1988, and served as Vice President of Finance from 1995 until 2003.

8

Table of Contents

Thomas P. Meissner, Jr. has been Unitil’s Senior Vice President and Chief Operating Officer since June 2005. Mr. Meissner served as Senior Vice President, Operations, from February 2003 until June 2005. Mr. Meissner joined Unitil in 1994 and served as Director of Engineering from 1998 until 2003.

Todd R. Black has been Unitil’s Senior Vice President, External Affairs and Customer Relations, Unitil Service, since September 2009. Mr. Black joined Unitil in 1998 and served as Vice President, Sales and Marketing, for Usource from 1998 until 2003, and President of Usource from 2003 until 2009.

Laurence M. Brock has been Unitil’s Controller and Chief Accounting Officer since June 2005. Mr. Brock joined Unitil in 1995 as Vice President and Controller, and is a certified public accountant in the state of New Hampshire.

George E. Long, Jr. has been Unitil’s Vice President, Administration, Unitil Service, since February 2003. Mr. Long joined Unitil in 1994 and was Director, Human Resources, from 1998 until 2003.

Sandra L. Whitney has been Unitil’s Corporate Secretary and secretary of the Board of Directors since February 2003. Ms. Whitney joined Unitil in 1990 and also serves as the Corporate Secretary of Unitil’s subsidiary companies.

William D. Adams has been a member of Unitil’s Board of Directors since March 2009, and his current term will expire in 2015. Mr. Adams has been the president of Colby College in Waterville, Maine, since 2000, and as president, Mr. Adams also serves on the board of trustees of Colby College. Prior to going to Colby, Mr. Adams served as president of Bucknell University in Pennsylvania from 1995 until 2000. Mr. Adams served as vice president and secretary of Wesleyan University in Connecticut, before Bucknell. Mr. Adams also taught political philosophy at the University of North Carolina at Chapel Hill and Santa Clara University, and was coordinator of the Great Works in Western Culture program at Stanford University. Mr. Adams has been a member of the board of directors of Maine Public Broadcasting Corporation since 2002. Mr. Adams formerly served on the board of directors of Wittenberg University from 2007—2011, and also the board of directors of Maine General Health from 2002 to 2010.

Dr. Robert V. Antonucci has been a member of Unitil’s Board of Directors since December 2004, and his current term will expire in 2014. Dr. Antonucci has been the president of Fitchburg State University (FSU) in Fitchburg, Massachusetts, since 2003. Prior to his employment with FSU, Dr. Antonucci was president of the School Group of Riverdeep, Inc., San Francisco, California, from 2001 until 2003 and president and chief executive officer of Harcourt Learning Direct and Harcourt Online College, Chestnut Hill, Massachusetts from 1998 until 2001. Dr. Antonucci also served as the commissioner of education for the Commonwealth of Massachusetts from 1992 until 1998. In addition, Dr. Antonucci has served as a trustee of Eastern Bank since 1988. Dr. Antonucci also serves as a director of the North Central Massachusetts Chamber of Commerce and a director of the North Central Massachusetts United Way.

David P. Brownell has been a member of Unitil’s Board of Directors since June 2001, and his current term will expire in 2014. Mr. Brownell has been a retired senior vice president of Tyco International Ltd. (Tyco) (a diversified global manufacturing and service company), Portsmouth, New Hampshire, since 2003. Mr. Brownell had been with Tyco since 1984. Mr. Brownell is a member of the board of the University of New Hampshire (UNH) Foundation. Mr. Brownell was also interim president of the UNH Foundation, former vice chairman of the board of the UNH Foundation, former volunteer board president of the United Way of the Greater Seacoast, and a former board member of the New Hampshire Junior Achievement Advisory Council.

Lisa Crutchfield has been a member of Unitil’s Board of Directors since December 2012. Ms. Crutchfield will stand for election to the Board of Directors at the Annual Meeting of Shareholders in April 2013. Ms. Crutchfield served as executive vice president of regulation and pricing for National Grid USA (National Grid), an international electric and gas company, in Waltham, Massachusetts, from 2008 to 2011. Prior to joining National Grid, Ms. Crutchfield served as senior vice president for regulatory and external affairs for PECO Energy Company, an Exelon Corporation company, located in Philadelphia, Pennsylvania from 2003 until 2008, and vice president of energy policy and strategy for Duke Energy Corporation in Charlotte, North Carolina from 1997 until 2000. Ms. Crutchfield also served as Vice Chairman of the Pennsylvania Public Utilities Commission from 1993 until 1997. Ms. Crutchfield recently

9

Table of Contents

served as a member of the U.S. Department of Energy Electricity Advisory Committee from 2010 to 2012. She also was a member of the board of trustees for the University of Pennsylvania from 2005 to 2008 and for the University of North Carolina at Charlotte from 2000 to 2003.

Michael J. Dalton has been a member of Unitil’s Board of Directors since September 1984, and his current term will expire in 2013. Mr. Dalton will retire from the Board of Directors following the Annual Meeting of Shareholders in April 2013 as he has reached the mandatory retirement age of 72. Mr. Dalton retired as President and Chief Operating Officer of Unitil in 2003. Mr. Dalton is a member of the College Advisory Board of the UNH College of Engineering and Physical Science and President of the Alumni Society of the College of Engineering and Physical Science. Mr. Dalton was formerly a director of the New England Gas Association, the Electric Council of New England, the UNH Foundation, the UNH Alumni Association, and the UNH President’s Council.

Albert H. Elfner, III has been a member of Unitil’s Board of Directors since January 1999, and his current term will expire in 2014. Mr. Elfner was the chairman of Evergreen Investment Management Company, Boston, Massachusetts, from 1994 until 1999 and its chief executive officer from 1995 until 1999. Mr. Elfner serves as a director of Main Street America Insurance Company (Main Street), Jacksonville, Florida, as well as chairman of the Main Street finance committee. Mr. Elfner is also a Chartered Financial Analyst.

Edward F. Godfrey has been a member of Unitil’s Board of Directors since January 2002 and his current term will expire in 2013. Mr. Godfrey will stand for re-election to the Board of Directors at the Annual Meeting of Shareholders in April 2013. Mr. Godfrey was the executive vice president and chief operating officer of Keystone Investments, Incorporated (Keystone), Boston, Massachusetts, from 1997 until 1998. Mr. Godfrey was senior vice president, chief financial officer and treasurer of Keystone from 1988 until 1996. Mr. Godfrey is also a director of Vector Fleet Management, LLC, Charlotte, North Carolina, since 2006.

Michael B. Green has been a member of Unitil’s Board of Directors since June 2001, and his current term will expire in 2014. Mr. Green has been the president and chief executive officer of Capital Region Health Care and Concord Hospital, Concord, New Hampshire, since 1992. Mr. Green is also a member of the adjunct faculty, Dartmouth Medical School, Dartmouth College, Hanover, New Hampshire. In addition, Mr. Green currently serves on the board of the Foundation for Healthy Communities, is a director of Concord General Mutual Insurance Company, and a director of Merrimack County Savings Bank (Merrimack), including membership on Merrimack’s investment and audit committees.

Eben S. Moulton has been a member of Unitil’s Board of Directors since March 2000, and his current term will expire in 2013. Mr. Moulton will stand for re-election to the Board of Directors at the Annual Meeting of Shareholders in April 2013. Mr. Moulton has been the managing partner of Seacoast Capital Corporation (a private investment company), of Danvers, Massachusetts, since 1995. Mr. Moulton is also a director of IEC Electronics Corp. (a company that provides electronic manufacturing services to advanced technology companies), Newark, New York, and a director of six private companies.

M. Brian O’Shaughnessy has been a member of Unitil’s Board of Directors since September 1998, and his current term will expire in 2014. Mr. O’Shaughnessy has been the chairman of the board of Revere Copper Products, Inc. (Revere), Rome, New York, since 1989. Mr. O’Shaughnessy also served as chief executive officer and president of Revere from 1988 until 2007. Mr. O’Shaughnessy also serves on the Board of Directors of three copper industry trade associations, three manufacturing associations in New York State regarding energy-related issues, the Economic Development Growth Enterprise (EDGE) of the Mohawk Valley and the Coalition for a Prosperous America (CPA). Mr. O’Shaughnessy is the chief co-chair of CPA.

Dr. Sarah P. Voll has been a member of Unitil’s Board of Directors since January 2003, and her current term will expire in 2015. Dr. Voll retired in 2007 as vice president from National Economic Research Associates, Inc. (NERA), Washington, District of Columbia, a firm of consulting economists specializing in industrial and financial economics, and currently serves as a special consultant to NERA. Dr. Voll had been with NERA in the position of vice president since 1999, and in the position of senior consultant from 1996 until 1999. Prior to her employment with NERA, Dr. Voll was a staff member at the NHPUC from 1980 until 1996.

10

Table of Contents

David A. Whiteley has been a member of Unitil’s Board of Directors since December 2012. Mr. Whiteley will stand for election to the Board of Directors at the Annual Meeting of Shareholders in April 2013. Mr. Whiteley has been the owner of Whiteley BPS Planning Ventures LLC, St. Louis, Missouri, a private consulting firm specializing in utility planning, operations, and management, since 2009. He has also served as the executive director of the Eastern Interconnection Planning Collaborative since 2011. Mr. Whiteley served as an executive vice-president of the North American Electric Reliability Corporation from 2007 to 2009. Prior to that, Mr. Whiteley served as senior vice president—Energy Delivery Services for Ameren Corporation, a multi-state electric and gas utility, headquartered in St. Louis, Missouri from 2005 to 2007 and as senior vice president—Energy Delivery, from 2003 to 2005. Mr. Whiteley started his employment at Ameren Corporation’s predecessor, Union Electric Company, in 1978. Mr. Whiteley is a registered professional engineer in the states of Missouri and Illinois.

INVESTOR INFORMATION

Annual Meeting

The Company’s annual meeting of shareholders is scheduled to be held at the offices of the Company, 6 Liberty Lane West, Hampton, New Hampshire, on Thursday, April 18, 2013, at 10:30 a.m.

Transfer Agent

The Company’s transfer agent, Computershare Investor Services, is responsible for shareholder records, issuance of common stock, administration of the Dividend Reinvestment and Stock Purchase Plan, and the distribution of Unitil’s dividends and IRS Form 1099-DIV. Shareholders may contact Computershare at:

Computershare Investor Services

P.O. Box 43078

Providence, RI 02940-3078

Telephone: 800-736-3001

www.computershare.com/investor

Investor Relations

For information about the Company, you may call the Company directly, toll-free, at: 800-999-6501 and ask for the Investor Relations Representative; visit the Investors page at www.unitil.com; or contact the transfer agent, Computershare, at the number listed above.

Special Services & Shareholder Programs Available to Holders of Record

If a shareholder’s shares of our common stock are registered directly in the shareholder’s name with the Company’s transfer agent, the shareholder is considered a holder of record of the shares. The following services and programs are available to shareholders of record:

To enroll, please contact the Company’s Investor Relations Representative or Computershare.

To enroll, please contact the Company’s Investor Relations Representative or Computershare.

For information, please contact Computershare at 800-935-9330 or the Company’s Investor Relations Representative at 800-999-6501.

11

Table of Contents

Risks Relating to Our Business

The Company is subject to comprehensive regulation, which could adversely impact the rates it is able to charge, its authorized rate of return and its ability to recover costs. In addition, certain regulatory authorities have the power to impose financial penalties and other sanctions on the Company, which could adversely affect the Company’s financial condition or results of operations.

The Company is subject to comprehensive regulation by federal regulatory authorities (including the FERC) and state regulatory authorities (including the NHPUC, MDPU and MPUC). These authorities regulate many aspects of the Company’s operations, including the rates that the Company can charge customers, the Company’s authorized rates of return, the Company’s ability to recover costs from its customers, construction and maintenance of the Company’s facilities, the Company’s safety protocols and procedures, the Company’s ability to issue securities, the Company’s accounting matters, and transactions between the Company and its affiliates. The Company is unable to predict the impact on its financial condition or results of operations from the regulatory activities of any of these regulatory authorities. Changes in regulations, the imposition of additional regulations or regulatory decisions particular to the Company could adversely affect the Company’s financial condition or results of operations.

The Company’s ability to obtain rate adjustments to maintain its current authorized rates of return depends upon action by regulatory authorities under applicable statutes, rules and regulations. These regulatory authorities are authorized to leave the Company’s rates unchanged, to grant increases in such rates or to order decreases in such rates. The Company may be unable to obtain favorable rate adjustments or to maintain its current authorized rates of return, which could adversely affect its financial condition or results of operations.

Regulatory authorities also have authority with respect to the Company’s ability to recover its electricity and natural gas supply costs, as incurred by Unitil Power, Unitil Energy, Fitchburg, and Northern Utilities. If the Company is unable to recover a significant amount of these costs, or if the Company’s recovery of these costs is significantly delayed, then the Company’s financial condition or results or operations could be adversely affected.

In addition, certain regulatory authorities have the power to impose financial penalties and other sanctions on the Company if the Company is found to have violated statutes, rules or regulations governing its utility operations. Any such penalties or sanctions could adversely affect the Company’s financial condition or results of operations.

Severe weather events have struck, and may strike, the New England region, causing extensive damage to the Company’s utility operations and the loss of service to significant numbers of the Company’s customers. If the Company is unable to recover a significant amount of storm costs in its rates, or if the Company’s recovery of storm costs in its rates is significantly delayed, then the Company’s financial condition or results of operations could be adversely affected.

The New England region in which the Company operates has been and will likely continue to be struck from time to time by severe weather events, including snow, wind and ice storms. These storms have in the past caused extensive damage to the Company’s utility operations and loss of service to the Company’s customers, and future severe weather events are likely to do so as well. If the Company cannot recover a significant amount of storm costs in its rates, or if the recovery of these costs is significantly delayed, then the Company’s financial condition and results of operations could be adversely affected. Please see the sections entitled Regulatory Matters in Item 7 (Management’s Discussion and Analysis of Financial Condition and Results of Operation) and Regulatory Matters in Note 5 (Commitments and Contingencies) to the Company’s Consolidated Financial Statements for a more detailed discussion of the effects of severe weather events on the Company’s financial condition and results of operations.

12

Table of Contents

As a result of electric industry restructuring, the Company has a significant amount of stranded electric generation and power supply related supply costs. If the Company is unable to recover a significant amount of stranded costs in its rates, or if the Company’s recovery of stranded costs in its rates is significantly delayed, then the Company’s financial condition or results of operations could be adversely affected.

The stranded electric generation and power supply related supply costs resulting from the implementation of electric industry restructuring mandated by the states of New Hampshire and Massachusetts are recovered by the Company on a pass-through basis through periodically reconciled rates. Any unrecovered balance of stranded costs is deferred for future recovery as a regulatory asset. Such regulatory assets are subject to periodic regulatory review and approval for recovery in future periods.

In connection with the implementation of retail choice, Unitil Power and Fitchburg divested their long-term power supply contracts through the sale of the entitlements to the electricity sold under those contracts. Unitil Energy and Fitchburg recover in their rates all the costs associated with the divestiture of their power supply portfolios and have secured regulatory approval from the NHPUC and MDPU, respectively, for the recovery of power supply-related stranded costs and other restructuring-related regulatory assets. The remaining balance of these assets, to be recovered principally over the next one to two years, is $24.3 million as of December 31, 2012, including $13.3 million recorded in Current Assets as Accrued Revenue on the Company’s Consolidated Balance Sheet. Unitil’s distribution companies have a continuing obligation to submit filings in both states that demonstrate their compliance with regulatory mandates and provide for timely recovery of costs in accordance with their approved restructuring plans.

If the Company is unable to recover a significant amount of such stranded costs in its rates, or if the Company’s recovery of such stranded costs in its rates is significantly delayed, then the Company’s financial condition or results or operations could be adversely affected. Please see the sections entitled Regulatory Matters—Overview in Item 7 (Management’s Discussion and Analysis of Financial Condition and Results of Operations) and Regulatory Matters—Overview in Note 5 (Commitments and Contingencies) to the accompanying Consolidated Financial Statements for a more detailed discussion of the effect of various regulatory matters on the Company and its subsidiaries.

The Company’s electric and natural gas sales and revenues are highly correlated with the economy, and national, regional and local economic conditions may adversely affect the Company’s customers and correspondingly the Company’s financial condition or results of operations.

The Company’s business is influenced by the economic activity within its service territory. The level of economic activity in the Company’s electric and natural gas distribution service territory directly affects the Company’s business. As a result, adverse changes in the economy may adversely affect the Company’s financial condition or results or operations.

The Company may not be able to obtain financing, or may not be able to obtain financing on acceptable terms, which could adversely affect the Company’s financial condition or results of operations.

The Company requires capital to fund utility plant additions, working capital and other utility expenditures. While the Company derives the capital necessary to meet these requirements primarily from internally-generated funds, the Company supplements internally generated funds by incurring short-term debt under its current credit facility, as needed. If the lending counterparties under the Company’s current credit facility are unwilling or unable to meet their funding obligations, then the Company may be unable to, or limited in its ability to, incur short-term debt under its credit facility. This could hinder or prevent the Company from meeting its current and future capital needs, which could correspondingly adversely affect the Company’s financial condition or results or operations.

Also, from time to time, the Company repays portions of its short-term debt with the proceeds it receives from long-term debt financings or equity financings. General economic conditions, conditions in the capital and credit markets and the Company’s operating and financial performance could negatively affect the Company’s ability to obtain such financings or the terms of such financings, which could correspondingly adversely affect the Company’s financial condition or results or operations.

13

Table of Contents

Declines in the valuation of capital markets could require the Company to make substantial cash contributions to cover its pension obligations. If the Company is unable to recover a significant amount of pension obligation costs in its rates, or if the Company’s recovery of pension obligation costs in its rates is significantly delayed, then the Company’s financial condition or results of operations could be adversely affected.

The amount of cash contributions the Company is required to make in respect of its pension obligations is dependent upon the valuation of the capital markets. Adverse changes in the valuation of the capital markets could result in the Company being required to make substantial cash contributions in respect of its pension obligations. These cash contributions could have an adverse effect on the Company’s financial condition and results of operations if the Company is unable to recover a such costs in rates or if such recovery is significantly delayed. Please see the section entitled Critical Accounting Policies—Pension Benefit Obligations in Item 7 (Management’s Discussion and Analysis of Financial Condition and Results of Operations) and Note 9 (Retirement Benefit Plans) to the accompanying Consolidated Financial Statements for a more detailed discussion of the Company’ pension obligations.

Increases in interest rates could increase the Company’s interest expense and adversely affect the Company’s financial condition or results of operations.

The Company and its utility subsidiaries have ongoing capital expenditure and cash funding requirements, which they frequently fund by issuing short-term debt and long-term debt.

The Company’s short-term debt revolving credit facility typically has variable interest rates. Therefore, an increase or decrease in interest rates will increase or decrease the Company’s interest expense associated with its revolving credit facility. An increase in the Company’s interest expense could adversely affect the Company’s financial condition or results of operations. As of December 31, 2012, the Company had approximately $49.4 million in short-term debt outstanding under its revolving credit facility.

The Company’s long-term debt typically has fixed interest rates. Therefore, changes in interest rates will not affect the Company’s interest expense associated with its presently outstanding fixed rate long-term debt. However, an increase or decrease in interest rates may increase or decrease the Company’s interest expense associated with any new fixed rate long-term debt issued by the Company, which could adversely affect the Company’s financial condition or results of operations. See the sections entitled Liquidity, Commitments and Capital Requirements in Item 7 (Management’s Discussion and Analysis of Financial Condition and Results of Operations) and Note 3 (Long-Term Debt, Credit Arrangements, Leases and Guarantees) to the accompanying Consolidated Financial Statements for a more detailed discussion of the effects of changes in interest rates on the Company.

In addition, the Company may need to use a significant portion of its cash flow to repay its short-term debt and long-term debt, which would limit the amount of cash it has available for working capital, capital expenditures and other general corporate purposes and could adversely affect its financial condition or results of operations.

The terms of the Company’s and its subsidiaries’ indebtedness restrict the Company’s and its subsidiaries’ business operations (including their ability to incur material amounts of additional indebtedness), which could adversely affect the Company’s financial condition or results of operations.

The terms of the Company’s and its subsidiaries’ indebtedness impose various restrictions on the Company’s business operations, including the ability of the Company and its subsidiaries to incur additional indebtedness. These restrictions could adversely affect the Company’s financial condition or results of operations. See the sections entitled Liquidity, Commitments and Capital Requirements in Item 7 (Management’s Discussion and Analysis of Financial Condition and Results of Operations) and Note 3 (Long-Term Debt, Credit Arrangements, Leases and Guarantees) to the accompanying Consolidated Financial Statements for a more detailed discussion of these restrictions.

14

Table of Contents

A significant amount of the Company’s sales are temperature sensitive. Because of this, mild winter and summer temperatures could decrease the Company’s sales, which could adversely affect the Company’s financial condition or results of operations. Also, the Company’s sales may vary from year to year depending on weather conditions, and the Company’s results of operations generally reflect seasonality.

The Company estimates that approximately 60% of its annual natural gas sales are temperature sensitive. Therefore, mild winter temperatures could decrease the amount of natural gas sold by the Company, which could adversely affect the Company’s financial condition or results of operations. The Company’s electric sales also are temperature sensitive, but less so than its natural gas sales. The highest usage of electricity typically occurs in the summer months (due to air conditioning demand) and the winter months (due to heating-related and lighting requirements). Therefore, mild summer temperatures and mild winter temperatures could decrease the amount of electricity sold by the Company, which could adversely affect the Company’s financial condition and results of operations. Also, because of this temperature sensitivity, sales by the Company’s distribution utilities vary from year to year, depending on weather conditions.

In addition, the Company’s results of operations generally reflect seasonality. In particular, the Company expects that results of operations will be positively affected during the first and fourth quarters, when sales of natural gas are typically higher (due to heating-related requirements), and negatively affected during the second and third quarters, when gas operating and maintenance expenses usually exceed sales margins in the period.

Long-term global climate change could adversely affect customer demand or cause extreme weather events that could disrupt the Company’s electric and natural gas distribution services.

Milder winter and summer temperatures that may be due to long-term global climate change could cause a decrease in the amount of natural gas and electricity sold by the Company. Conversely, colder winter temperatures and warmer summer temperatures that may be due to long-term global climate change could cause an increase in the amount of natural gas and electricity sold by the Company.

In addition, extreme weather events (such as hurricanes and severe winter storms) that may be related to long-term global climate change could damage facilities or result in increased service interruptions and outages and increase the Company’s operations and maintenance costs. If the Company is unable to recover a significant amount of such costs in its rates, or if the Company’s recovery of such costs in its rates is significantly delayed, then the Company’s financial condition or results or operations may be adversely affected.

The Company is unable to predict the impacts on its financial condition and results or operations due to changes in weather that may be related to long-term global climate change.

Unitil is a public utility holding company and has no operating income of its own. The Company’s ability to pay dividends on its common stock is dependent on dividends and other payments received from its subsidiaries and on factors directly affecting Unitil, the parent corporation. The Company cannot assure that its current annual dividend will be paid in the future.

The ability of the Company’s subsidiaries to pay dividends or make distributions to Unitil depends on, among other things:

15

Table of Contents

In addition, before the Company can pay dividends on its common stock, it has to satisfy its debt obligations and comply with any statutory or contractual limitations.

The Company’s current annual dividend is $1.38 per share of common stock, payable quarterly. However, the Company’s Board of Directors reviews Unitil’s dividend policy periodically in light of the factors referred to above, and the Company cannot assure the amount of dividends, if any, that may be paid in the future.

The Company’s electric and natural gas distribution activities (including storing natural gas and supplemental gas supplies) involve numerous hazards and operating risks that may result in accidents and other operating risks and costs. Any such accident or costs could adversely affect the Company’s financial position and results of operations.

Inherent in the Company’s electric and natural gas distribution activities are a variety of hazards and operating risks, including leaks, explosions, electrocutions and mechanical problems. These hazards and risks could result in loss of human life, significant damage to property, environmental pollution, damage to natural resources and impairment of the Company’s operations, which could adversely affect the Company’s financial position and results of operations.

The Company maintains insurance against some, but not all, of these risks and losses in accordance with customary industry practice. The location of pipelines, storage facilities and electric distribution equipment near populated areas (including residential areas, commercial business centers and industrial sites) could increase the level of damages associated with these hazards and operating risks. The occurrence of any of these events could adversely affect the Company’s financial position or results of operations.

The Company’s business is subject to environmental regulation in all jurisdictions in which it operates and its costs of compliance are significant. New, or changes to existing, environmental regulation, including those related to climate change or greenhouse gas emissions, and the incurrence of environmental liabilities could adversely affect the Company’s financial condition or results of operations.

The Company’s utility operations are generally subject to extensive federal, state and local environmental laws and regulations relating to air quality, water quality, waste management, natural resources, and the health and safety of the Company’s employees. The Company’s utility operations also may be subject to new and emerging federal, state and local legislative and regulatory initiatives related to climate change or greenhouse gas emissions including the U.S. Environmental Protection Agency’s mandatory greenhouse gas reporting rule. Failure to comply with these laws and regulations may result in the assessment of administrative, civil, and criminal penalties and other sanctions; imposition of remedial requirements; and issuance of injunctions to ensure future compliance. Liability under certain environmental laws and regulations is strict, joint and several in nature. Although the Company believes it is in material compliance with all applicable environmental and safety laws and regulations, we cannot assure you that the Company will not incur significant costs and liabilities in the future. Moreover, it is possible that other developments, such as increasingly stringent federal, state or local environmental laws and regulations, including those related to climate change or greenhouse gas emissions, could result in increased environmental compliance costs.

Catastrophic events could adversely affect the Company’s financial condition or results of operations.

The electric and natural gas utility industries are from time to time affected by catastrophic events, such as unusually severe weather and significant and widespread failures of plant and equipment. Other catastrophic occurrences, such as terrorist attacks on utility facilities, may occur in the future. Such events could inhibit the Company’s ability to provide electric or natural gas distribution services to its customers for an extended period, which could adversely affect the Company’s financial condition and results of operations.

16

Table of Contents

The Company’s operational and information systems on which it relies to conduct its business and serve customers could fail to function properly due to technological problems, a cyber-attack, acts of terrorism, severe weather, a solar event, an electromagnetic event, a natural disaster, the age and condition of information technology assets, human error, or other reasons, that could disrupt the Company’s operations and cause the Company to incur unanticipated losses and expense.

The operation of the Company’s extensive electricity and natural gas systems rely on evolving information technology systems and network infrastructures that are likely to become more complex as new technologies and systems are developed to establish a “Smart Grid” to monitor and manage the nation’s interconnected electric transmission grids. The Company’s business is highly dependent on its ability to process and monitor, on a daily basis, a very large number of transactions, many of which are highly complex. The failure of these information systems and networks could significantly disrupt operations; result in outages and/or damages to the Company’s assets or operations or those of third parties on which it relies; and subject the Company to claims by customers or third parties, any of which could have a material effect on the Company’s financial condition, results of operations, and cash flows.

The Company’s information systems, including its financial information, operational systems, metering, and billing systems, require constant maintenance, modification, and updating, which can be costly and increases the risk of errors and malfunction. Any disruptions or deficiencies in existing information systems, or disruptions, delays or deficiencies in the modification or implementation of new information systems, could result in increased costs, the inability to track or collect revenues, the diversion of management’s and employees’ attention and resources, and could negatively impact the effectiveness of the Company’s control environment, and/or the Company’s ability to timely file required regulatory reports. Despite implementation of security and mitigation measures, all of the Company’s technology systems are vulnerable to impairment or failure due to cyber-attacks, viruses, human errors, acts of war or terrorism and other reasons. If the Company’s information technology systems were to fail or be materially impaired, the Company might be unable to fulfill critical business functions and serve its customers, which could have a material effect on the Company’s financial conditions, results of operations, and cash flows.

In addition, in the ordinary course of its business, the Company collects and retains sensitive information including personal identification information about customers and employees, customer energy usage, and other confidential information. The theft, damage, or improper disclosure of sensitive electronic data could subject the Company to penalties for violation of applicable privacy laws or claims from third parties and could harm the Company’s reputation.

Public utility companies are subject to adverse publicity and reputational risks, which make them vulnerable to negative customer perception and increased regulatory oversight or other sanctions.

Utility companies, including the Company’s distribution utility subsidiaries, have a large consumer customer base and, as a result, are subject to public criticism focused on the reliability of their distribution services and the speed with which they are able to respond to outages caused by storm damage or other unanticipated events. Adverse publicity of this nature may render legislatures, public utility commissions and other regulatory authorities and government officials, less likely to view public utility companies in a favorable light, and may cause the Company to be susceptible to less favorable legislative and regulatory outcomes or increased regulatory oversight. Unfavorable regulatory outcomes can include more stringent laws and regulations governing the Company’s operations, such as reliability and customer service quality standards or vegetation management requirements, as well as fines, penalties or other sanctions or requirements. The imposition of any of the foregoing could have a material negative impact on the Company’s results of operations, cash flow and financial condition.

The Company’s business could be adversely affected if it is unable to retain its existing customers or attract new customers.

The success of the Company’s business depends, in part, on its ability to maintain and increase its customer base. The Company’s failure to maintain or increase its customer base could adversely affect its financial condition and results of operations.

17

Table of Contents

The Company’s energy brokering customers may default in their performance under multi-year energy brokering contracts, which could adversely affect the Company’s financial condition and results of operations.

The Company’s non-regulated energy brokering business provides energy brokering and consulting services to a national client base of large commercial and industrial customers. Revenues from this business are primarily derived from brokering fees and charges billed to suppliers as customers take delivery of energy from these suppliers under term contracts. The Company’s customers may default in their performance under multi-year energy brokering contracts, which could adversely affect the Company’s financial condition and results of operations.

Our stock price may decline when our results decline or when events occur that are adverse to us or our industry.

The market price of our common stock may decline when our results of operations decline or at any time when events actually or potentially adverse to us or the natural gas and electric industry occur.

None.

As of December 31, 2012, Unitil owned, through its electric distribution utilities, three utility operation centers, approximately 1,702 primary pole miles of local transmission and distribution overhead electric lines and 263 conduit bank miles of underground electric distribution lines, along with 49 electric substations, including four mobile electric substations. The Company’s natural gas operations property includes two liquid propane gas plants, two liquid natural gas plants and 1,299 miles of underground gas mains. In addition, the Company’s real estate subsidiary, Unitil Realty, owns the Company’s corporate headquarters building and the 12 acres of land on which it is located.

Unitil Energy owns and maintains distribution operations centers in Concord, New Hampshire and Kensington, New Hampshire. Unitil Energy’s 33 electric distribution substations, including a 5,000 kilovolt ampere (kVA) and a 10,500 kVA mobile substation, constitute 215,400 kVA of capacity, which excludes capacity of spare transformers, for the transformation of electric power from the 34.5 kilovolt subtransmission voltage to other primary distribution voltage levels. The electric substations are located on land owned by Unitil Energy or land occupied by Unitil Energy pursuant to perpetual easements.

Unitil Energy has a total of approximately 1,263 primary pole miles of local transmission and distribution overhead electric lines and a total of 204 conduit bank miles of underground electric distribution lines. The electric distribution lines are located in, on or under public highways or private lands pursuant to lease, easement, permit, municipal consent, tariff conditions, agreement or license, expressed or implied through use by Unitil Energy without objection by the owners. In the case of certain distribution lines, Unitil Energy owns only a part interest in the poles upon which its wires are installed, the remaining interest being owned by telephone companies.

The physical utility properties of Unitil Energy, with certain exceptions, and its franchises are subject to its indenture of mortgage and deed of trust under which the respective series of first mortgage bonds of Unitil Energy are outstanding.

Fitchburg’s electric properties consist principally of 439 primary pole miles of local transmission and distribution overhead electric lines, 59 conduit bank miles of underground electric distribution lines and 16 transmission and distribution stations, including two mobile electric substations. The capacity of these substations totals 441,700 kVA, which excludes capacity of spare transformers.

Fitchburg’s electric substations, with minor exceptions, are located on land owned by Fitchburg or occupied by Fitchburg pursuant to perpetual easements. Fitchburg’s electric distribution lines and gas mains

18

Table of Contents

are located in, on or under public highways or private lands pursuant to lease, easement, permit, municipal consent, tariff conditions, agreement or license, express or implied through use by Fitchburg without objection by the owners. Fitchburg leases its distribution operations center located in Fitchburg, Massachusetts.

Fitchburg owns a propane air gas plant and a liquid natural gas (LNG) storage and vaporization facility, both of which are located on land owned by Fitchburg. Fitchburg also has 270 miles of underground steel, cast iron and plastic gas mains and 10,863 active gas services. The gas mains are primarily made up of steel (50%), polyethylene plastic (25%), and cast iron (25%).

Northern Utilities’ distribution system is comprised of 1,029 miles of gas mains and 40,254 service pipes. The gas mains are primarily made up of polyethylene plastic (72%), coated and wrapped cathodically protected steel (18%), cast/wrought iron (6%), and unprotected bare and coated steel (4%).

Northern Utilities’ New Hampshire division serving 21 communities has 502 miles of distribution gas mains and 21,502 service pipes. Northern Utilities’ Maine division serving 23 communities has 527 miles of distribution gas main and 18,752 service pipes. Northern Utilities also owns a propane air gas plant and a LNG storage and vaporization facility.

Granite State is a natural gas transmission pipeline, regulated by the FERC, operating 86 miles of underground gas transmission pipeline located primarily in Maine and New Hampshire.

The Company believes that its facilities are currently adequate for their intended uses.

The Company is involved in legal and administrative proceedings and claims of various types, which arise in the ordinary course of business. The Company believes, based upon information furnished by counsel and others, that the ultimate resolution of these claims will not have a material impact on the Company’s financial position.

In early 2009, a putative class action complaint was filed against Unitil Corporation’s (the “Company”) Massachusetts based utility, Fitchburg Gas and Electric Light Company (“Fitchburg”), in Massachusetts’ Worcester Superior Court (the “Court”), (captioned Bellerman et al v. Fitchburg Gas and Electric Light Company). The Complaint seeks an unspecified amount of damages, including the cost of temporary housing and alternative fuel sources, emotional and physical pain and suffering and property damages allegedly incurred by customers in connection with the loss of electric service during the ice storm in Fitchburg’s service territory in December, 2008. The Complaint, as amended, includes M.G.L. ch. 93A claims for purported unfair and deceptive trade practices related to the December 2008 ice storm. On September 4, 2009, the Superior Court issued its order on the Company’s Motion to Dismiss the Complaint, granting it in part and denying it in part. Following several years of discovery, the plaintiffs in the complaint filed a motion with the Court to certify the case as a class action. On January 7, 2013, the Court issued its decision denying plaintiffs’ motion to certify the case as a class action. As a result of this decision, the lawsuit will now continue with only the twelve named plaintiffs seeking damages. Future proceedings may include an appeal of this decision or a trial on the claims of the twelve named plaintiffs. The Company continues to believe the suit is without merit and will continue to defend itself vigorously.

Not applicable.

19

Table of Contents

PART II

Our common stock is listed on the New York Stock Exchange under the symbol “UTL.” As of December 31, 2012, there were 1,534 shareholders of record of our common stock.

Common Stock Data

See also “Dividends” in Part II, Item 7 (Management’s Discussion and Analysis of Financial Condition and Results of Operations) below.

Information regarding securities authorized for issuance under our equity compensation plans, as of December 31, 2012, is set forth in the table below.

Equity Compensation Plan Information

NOTES: (also see Note 2 to the accompanying Consolidated Financial Statements)

20

Table of Contents

Stock Performance Graph

The following graph compares Unitil Corporation’s cumulative stockholder return since December 31, 2007 with the Peer Group index, comprised of the S&P 500 Utilities Index, and the S&P 500 index. The graph assumes that the value of the investment in the Company’s common stock and each index (including reinvestment of dividends) was $100 on December 31, 2007.

Comparative Five-Year Total Returns

NOTE:

21

Table of Contents

Unregistered Sales of Equity Securities and Uses of Proceeds

There were no sales of unregistered equity securities by the Company for the fiscal period ended December 31, 2012.

Issuer Purchases of Equity Securities

Pursuant to the written trading plan under Rule 10b5-1 under the Securities Exchange Act of 1934, as amended (the Exchange Act), adopted by the Company on March 22, 2012, the Company will periodically repurchase shares of its Common Stock on the open market related to Employee Length of Service Awards and the stock portion of the Directors’ annual retainer. There is no pool or maximum number of shares related to these purchases; however, the trading plan will terminate when $200,800 in value of shares have been purchased or, if sooner, on March 22, 2013.

The Company may suspend or terminate this trading plan at any time, so long as the suspension or termination is made in good faith and not as part of a plan or scheme to evade the prohibitions of Rule 10b-5 under the Exchange Act, or other applicable securities laws.

The following table shows information regarding repurchases by the Company of shares of its common stock for each month in the quarter ended December 31, 2012.

22

Table of Contents

23

Table of Contents

OVERVIEW

Unitil is a public utility holding company headquartered in Hampton, New Hampshire. Unitil is subject to regulation as a holding company system by the FERC under the Energy Policy Act of 2005.

Unitil’s principal business is the local distribution of electricity and natural gas to approximately 175,400 customers throughout its service territory in the states of New Hampshire, Massachusetts and Maine. Unitil is the parent company of three wholly-owned distribution utilities:

Unitil Energy, Fitchburg and Northern Utilities are collectively referred to as the “distribution utilities.” Together, the distribution utilities serve approximately 101,700 electric customers and 73,700 natural gas customers in their service territory.

In addition, Unitil is the parent company of Granite State, a natural gas transmission pipeline, regulated by the FERC, operating 86 miles of underground gas transmission pipeline primarily located in Maine and New Hampshire. Granite State provides Northern Utilities with interconnection to three major natural gas pipelines and access to North American pipeline supplies.

The distribution utilities are local “pipes and wires” operating companies, and Unitil had an investment in Net Utility Plant of $601.2 million at December 31, 2012. Unitil’s total revenue was $353.1 million in 2012, which includes revenue to recover the approved cost of purchased electricity and natural gas in rates on a fully reconciling basis. As a result of this reconciling rate structure, the Company’s earnings are not affected by changes in the cost of purchased electricity and natural gas. Earnings from Unitil’s utility operations are derived from the return on investment in the three distribution utilities and Granite State.

Unitil also conducts non-regulated operations principally through Usource, which is wholly-owned by Unitil Resources. Usource provides energy brokering and consulting services to a national client base of large commercial and industrial customers. Usource’s total revenues were $5.5 million in 2012. The Company’s other subsidiaries include Unitil Service, which provides, at cost, a variety of administrative and professional services to Unitil’s affiliated companies, and Unitil Realty, which owns and manages Unitil’s corporate office building and property located in Hampton, New Hampshire. Unitil’s consolidated net income includes the earnings of the holding company and these subsidiaries.

Regulation

Unitil is subject to comprehensive regulation by federal and state regulatory authorities. Unitil and its subsidiaries are subject to regulation as a holding company system by the FERC under the Energy Policy Act of 2005 with regard to certain bookkeeping, accounting and reporting requirements. Unitil’s utility operations related to wholesale and interstate energy business activities are also regulated by the FERC. Unitil’s distribution utilities are subject to regulation by the applicable state public utility commissions, with regard to their rates, issuance of securities and other accounting and operational matters: Unitil Energy is subject to regulation by the New Hampshire Public Utilities Commission (NHPUC); Fitchburg is subject to regulation by the Massachusetts Department of Public Utilities (MDPU); and Northern Utilities is regulated by the NHPUC and Maine Public Utilities Commission (MPUC). Granite State, Unitil’s interstate natural gas transmission pipeline, is subject to regulation by the FERC with regard to its rates and operations. Because Unitil’s primary operations are subject to rate regulation, the regulatory treatment of various matters could significantly affect the Company’s operations and financial position.

24

Table of Contents

Unitil’s distribution utilities deliver electricity and/or natural gas to all customers in their service territory, at rates established under traditional cost of service regulation. Under this regulatory structure, Unitil’s distribution utilities recover the cost of providing distribution service to their customers based on a historical test year, in addition to earning a return on their capital investment in utility assets. In addition, the Company’s distribution utilities and its natural gas transmission pipeline company may also recover certain base rate costs, including capital project spending and enhanced reliability and vegetation management programs, through annual step adjustments and cost tracker rate mechanisms.

As a result of a restructuring of the utility industry in New Hampshire, Massachusetts and Maine, Unitil’s customers, with the exception of Northern Utilities’ residential customers, have the opportunity to purchase their electricity or natural gas supplies from third-party energy supply vendors. Most customers, however, continue to purchase such supplies through the distribution utilities under regulated energy rates and tariffs. Unitil’s distribution utilities purchase electricity or natural gas from unaffiliated wholesale suppliers and recover the actual approved costs of these supplies on a pass-through basis, as well as certain costs associated with industry restructuring, through reconciling rate mechanisms that are periodically adjusted.

In 2011 and 2012, the Company completed base rate cases for: Unitil Energy; the electric and gas divisions of Fitchburg; the New Hampshire and Maine divisions of Northern Utilities; and Granite State. The completion of these rate cases resulted in increases in annual distribution revenues of: $10.2 million for Unitil Energy; $3.3 million and $3.7 million for the electric and gas divisions of Fitchburg, respectively; and $3.7 million and $8.7 million for the New Hampshire and Maine divisions, respectively, of Northern Utilities. Granite State received approval for an increase of $2.2 million in annual revenue. Additionally, in 2011 and 2012, the Company completed rate filings that resulted in increases in annual revenues, through step adjustments and cost tracker rate mechanisms, of: $1.5 million for Unitil Energy; $0.5 million for the electric division of Fitchburg; and $0.3 million for Granite State.

On August 1, 2011, the MDPU issued an order approving revenue decoupling mechanisms (RDM) for the electric and natural gas divisions of Fitchburg. Revenue decoupling is the term given to the elimination of the dependency of a utility’s distribution revenue on the volume of its electricity or natural gas sales. One of the primary purposes of decoupling is to eliminate the disincentive a utility otherwise has to encourage and promote energy conservation programs designed to reduce energy usage. Under the RDM, the Company will recognize, in its Consolidated Statements of Earnings from August 1, 2011 forward, distribution revenues for Fitchburg based on established revenue targets. The established revenue targets for the gas division may be subject to periodic adjustments to account for customer growth and special contracts, for which RDM does not apply. The difference between distribution revenue amounts billed to customers and the targeted amounts is recognized as increases or decreases in Accrued Revenue which form the basis for future reconciliation adjustments in periodically resetting rates for future cash recoveries from, or credits to, customers. The Company estimates that RDM applies to approximately 27% and 11% of its annual electric and natural gas sales volumes, respectively. As a result, the sales margins resulting from those sales are no longer sensitive to weather and economic factors. The Company’s other electric and natural gas distribution utilities are not subject to RDM.

RESULTS OF OPERATIONS

The following discussion of the Company’s financial condition and results of operations should be read in conjunction with the accompanying Consolidated Financial Statements and the accompanying Notes to Consolidated Financial Statements included in Part II, Item 8 of this report.

The Company’s results of operations are expected to reflect the seasonal nature of the natural gas business. Annual gas revenues are substantially realized during the heating season as a result of higher sales of natural gas due to cold weather. Accordingly, the results of operations are historically most favorable in the first and fourth quarters. Fluctuations in seasonal weather conditions may have a significant effect on the result of operations. Sales of electricity are generally less sensitive to weather than natural gas sales, but may also be affected by the weather conditions in both the winter and summer seasons.

On May 16, 2012, the Company sold 2,760,000 shares of its common stock at a price of $25.25 per share in a registered public offering. The Company used the net proceeds of approximately $65.7 million

25

Table of Contents

from this offering to make equity capital contributions to its regulated utility subsidiaries, repay short-term debt and for general corporate purposes. Overall, the results of operations and Earnings reflect the higher number of average shares outstanding year over year.

Net Income and EPS Overview

2012 Compared to 2011—The Company’s Earnings Applicable to Common Shareholders (Earnings) were $18.1 million for the year ended December 31, 2012, an increase of $1.8 million, or 11%, over the $16.3 million the Company earned in 2011. Earnings per common share (EPS) were $1.43 for 2012 compared to $1.50 per share in 2011. As discussed above, the 2012 EPS reflect the higher number of average shares outstanding year over year.

The results for 2012 were positively affected by higher natural gas and electric sales margins due to higher distribution rates and new customer growth. Margins were negatively affected in 2012 by the effect on sales of fluctuations in seasonal weather conditions year over year. The Company estimates that the mild weather in 2012 negatively impacted earnings for the gas division by about $1.6 million, or $0.13 per share, and the electric division by about $0.1 million, or $0.01 per share. According to the National Oceanic and Atmospheric Administration, 2012 was the warmest year on record for the northeast region of the United States, in which the Company’s service areas are located.

The Company’s Earnings were $9.0 million, or $0.66 per share, for the fourth quarter of 2012, compared to Earnings of $10.0 million, or $0.92 per share, in the fourth quarter of 2011. Earnings for 2011 include a non-recurring pre-tax credit of $4.7 million recorded in the fourth quarter of that year in connection with the Company’s court appeal and the resulting favorable ruling vacating a 2009 regulatory order that had resulted in the previous charge off of Purchased Gas costs.

Natural gas sales margins were $76.2 million in 2012, or an increase of $8.3 million compared to 2011, reflecting higher gas distribution rates and new customer growth, partially offset by lower gas therm sales, principally in the first quarter of 2012, due to mild winter weather. Also, gas margins in 2011 include the one-time recovery of $4.5 million in Purchased Gas costs that had been charged off in a prior period. Based on weather data collected in the Company’s service areas, there were 11% and 16% fewer Heating Degree Days in 2012 compared to 2011 and normal, respectively. Weather-normalized gas therm sales (excluding decoupled sales) in 2012 are estimated to be 3.3% higher compared to 2011. Approximately 11% of natural gas therm sales are decoupled and changes in these sales due to the weather do not affect sales margins.

Electric sales margins were $71.9 million in 2012, or an increase of $4.3 million compared to 2011, reflecting higher electric distribution rates and new customer growth, partially offset by lower electric kilowatt hour (kWh) sales, principally in the first quarter of 2012, due to mild winter weather. Weather-normalized electric kWh sales (excluding decoupled sales) in 2012 are estimated to be about the same compared to 2011. Approximately 27% of electric kWh sales are decoupled and changes in these sales due to the weather do not affect sales margins.

Total Operation & Maintenance (O&M) expenses increased $5.5 million in 2012 compared to 2011. The change in O&M expenses reflects higher utility operating costs of $3.7 million, higher employee compensation and benefit costs of $0.5 million, and higher professional fees of $0.3 million. The increase in utility operating costs in 2012 compared to 2011 includes an increase of $2.6 million in new spending on vegetation management and electric reliability enhancement programs of which approximately $1.8 million is recovered through cost tracker rate mechanisms that result in corresponding and offsetting increase in revenue. Also, the increase in utility operating costs includes $0.5 million in higher bad debt expenses, $0.3 million in higher storm costs and an increase in all other utility operating costs, net of $0.3 million. The increase in O&M costs in 2012 over the prior year also reflects lower O&M expenses recorded in the first quarter of 2011 due to the receipt of a non-recurring insurance payment of $1.0 million.

Depreciation and Amortization expense increased $5.8 million in 2012 compared to 2011 principally reflecting normal utility plant additions and amortization of regulatory assets.

Local Property and Other Taxes increased $1.0 million in 2012 compared to 2011, reflecting higher local property taxes on higher levels of utility plant in service.

Federal and State Income Taxes increased $1.0 million in 2012 due to higher pre-tax earnings in 2012 compared to 2011.

26

Table of Contents

Other Non-operating Expenses decreased $0.2 million in 2012 compared to 2011.

Interest Expense, net decreased $2.3 million in 2012 compared to 2011 primarily reflecting lower interest rates and lower borrowing balances as a result of the equity offering in 2012 as well as the recognition of a non-recurring pre-tax charge, in 2011, against interest income of $1.8 million to charge-off previously accrued carrying costs that were disallowed for rate recovery.

Usource, the Company’s non-regulated energy brokering business, recorded revenues of $5.5 million in 2012, on par with 2011. Usource’s revenues are primarily derived from fees and charges billed to suppliers as customers take delivery of energy from these suppliers under term contracts brokered by Usource. The Company will also realize future fees estimated at the end of December 2012 of $8.2 million from executed energy supply term contracts running from 2013 through 2017.

In 2012, Unitil’s annual common dividend was $1.38, representing an unbroken record of quarterly dividend payments since trading began in Unitil’s common stock. At its January 2013 meeting, the Unitil Board of Directors declared a quarterly dividend on the Company’s common stock of $0.345 per share.

2011 Compared to 2010—The Company’s Earnings Applicable to Common Shareholders were $16.3 million, or $1.50 per share, for 2011, an increase of $6.8 million, or $0.62 per share, over 2010, reflecting higher natural gas and electric sales margins partially offset by higher utility operating and interest costs. The results include a non-recurring pre-tax credit of $4.7 million recorded in the fourth quarter of 2011 in connection with the Company’s court appeal and the resulting favorable ruling vacating a 2009 regulatory order that had resulted in the previous charge off of Purchased Gas costs. The results for 2011 also include a non-recurring pre-tax charge of $2.0 million recorded in the third quarter, related to the resolution of the 2008 ice storm cost recovery in the Company’s Massachusetts rate case and a credit of $1.0 million, recorded in the first quarter, for the proceeds from insurance related settlements.

A more detailed discussion of the Company’s 2012 and 2011 results of operations and a year-to-year comparison of changes in financial position are presented below.

Gas Sales, Revenues and Margin

Therm Sales—Unitil’s total therm sales of natural gas decreased 3.0% in 2012 compared to 2011. The decrease in gas therm sales in the Company’s utility service areas reflects the effect of milder winter weather in 2012 compared to 2011. Based on weather data collected in the Company’s service areas, there were 11% and 16% fewer Heating Degree Days in 2012 compared to 2011 and normal, respectively. Weather-normalized gas therm sales (excluding decoupled sales) in 2012 are estimated to be 3.3% higher compared to 2011. The increase in weather-normalized gas therm sales reflects the addition of new Residential and C&I business customers during the year. Approximately 11% of natural gas therm sales are decoupled and changes in these sales due to the weather do not affect sales margins. As discussed above, under revenue decoupling for Fitchburg, distribution revenues, which are included in sales margin, will be recognized in the Company’s Consolidated Statements of Earnings from August 1, 2011 forward, on established revenue targets and will no longer be dependent on sales volumes.

Unitil’s total therm sales of natural gas increased 8.1% in 2011 compared to 2010. The increase in gas therm sales reflects the addition of new Residential and C&I business customers during the year, increased gas usage and colder weather in 2011 compared to 2010, particularly in the first quarter of 2011. Heating Degree Days in 2011 were 3.8% greater than in 2010. Weather-normalized gas therm sales (excluding decoupled sales) in 2011 are estimated to be 8% higher compared to 2010.

The following table details total therm sales for the last three years, by major customer class:

27

Table of Contents

Gas Operating Revenues and Sales Margin—The following table details total Gas Operating Revenue and Margin for the last three years by major customer class: