Entry into a Material Definitive Agreement. On October 21, 2026, Maine Natural Gas Corporation (“Maine Natural”), a natural gas distribution utility subsidiary of Unitil Corporation (the “Company” or the “Registrant”), entered into a Note Purchase Agreement with Lincoln National Reinsurance Company (Barbados) Limited, The Lincoln National Life Insurance Company, and CoBank, ACB (the “Note Purchase Agreement”) pursuant to which it issued and sold $40,000,000 of 5.95% Senior Unsecured Notes, du…

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. The disclosure in

Termination of a Material Definitive Agreement. As previously reported, on June 30, 2026, the Company entered into an Amended and Restated Credit Agreement dated as of June 30, 2026 among the following parties (the “Credit Agreement”): the Company; The Bank of Nova Scotia, as agent; and The Bank of Nova Scotia, as lender. On October 22, 2026, the Company repaid all outstanding amounts under the Credit Agreement, without premium or penalty. The Company may not reborrow any portion of the repai…

Entry into a Material Definitive Agreement. On October 14, 2026, Unitil Energy Systems, Inc. (“ Unitil Energy ”), an electric distribution utility subsidiary of Unitil Corporation (the “Company” or the “Registrant”), entered into (i) a Bond Purchase Agreement with U.S. Bank Trust Company, National Association (as trustee), Metropolitan Life Insurance Company, Metropolitan Tower Life Insurance Company, Metlife Reinsurance Company of Hamilton, Ltd., State Farm Life Insurance Company, State Farm…

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. The disclosure in

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. The disclosure in

Entry into a Material Definitive Agreement. On September 24, 2026, Unitil Corporation (the “Company” or the “Registrant”) entered into a Note Purchase Agreement with CoBank, ACB, Thrivent Financial for Lutherans, Metlife Reinsurance Company of Hamilton, Ltd., Modern Woodmen of America and CMFG Life Insurance Company (the “Note Purchase Agreement”) pursuant to which the Company issued and sold (i) $27,000,000 of 5.42% Senior Unsecured Notes, Series 2026A, due September 24, 2031 and (ii) $33,00…

Entry into a Material Definitive Agreement. 1. Amendment No. 4 to Purchase and Sale Agreement. As previously reported, on May 6, 2025, Unitil Corporation, a New Hampshire corporation (“ Unitil ” or the “ Company ”), entered into a Purchase and Sale Agreement (as amended, the “ Purchase Agreement ”) by and between the Company and Aquarion Water Authority, a public corporation and political subdivision of the state of Connecticut (“ AWA ” or “ Seller ”), and, solely with respect to Section 9.25…

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. The disclosure in

Other Events. On June 30, 2026, Unitil and Seller completed Unitil’s acquisition of all of the outstanding shares of capital stock of AWC-NH and Abenaki from Seller pursuant to the Purchase Agreement. Pursuant to the Purchase Agreement, as consideration for the shares of capital stock of AWC-NH and Abenaki, Unitil paid Seller $42.1 million in cash for the stock, plus approximately $0.6 million for estimated working capital and reimbursable capital expenditures.

Regulation FD Disclosure. A press release announcing the completion of Unitil’s acquisition of AWC-NH and Abenaki is attached as Exhibit 99.1 to this Form 8-K.

Entry into a Material Definitive Agreement. Amendment to Purchase Agreement As previously reported, on May 6, 2025, Unitil Corporation, a New Hampshire corporation (the " Company "), entered into a Purchase and Sale Agreement (the “ Purchase Agreement ”) by and between the Company and Aquarion Water Authority, a public corporation and political subdivision of the state of Connecticut (“ Seller ”), and, solely with respect to Section 9.25 and Section 9.26 thereof, South Central Connecticut Reg…

Entry into a Material Definitive Agreement. On April 30, 2026, Fitchburg Gas and Electric Light Company (“Fitchburg”), an electric and natural gas distribution utility subsidiary of Unitil Corporation (the “Company” or the “Registrant”), entered into a Note Purchase Agreement with State Farm Life Insurance Company, State Farm Life and Accident Assurance Company and CoBank, ACB (the “Note Purchase Agreement”) pursuant to which it issued and sold (i) $23,000,000 of 5.62% Senior Unsecured Notes,…

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. The disclosure in

Entry into a Material Definitive Agreement Distribution Agreement As previously reported, on June 3, 2025, Unitil Corporation, a New Hampshire corporation (the “ Company ”), entered into a Distribution Agreement (the “ Distribution Agreement ”) with Janney Montgomery Scott LLC and Scotia Capital (USA) Inc., as agents and/or forward sellers, and Janney Montgomery Scott LLC and The Bank of Nova Scotia, as forward purchasers, pursuant to which the Company may sell, from time to time, up to an ag…

Entry into a Material Definitive Agreement The disclosure required by this item is included in

The filing describes amendments to the company's equity compensation practices, which is not a management change.

Entry into a Material Definitive Agreement Amendment to Purchase Agreement On May 6, 2025, Unitil Corporation, a New Hampshire corporation (the “ Company ”), entered into a Purchase and Sale Agreement (the “ Purchase Agreement ”) by and between the Company and Aquarion Water Authority, a public corporation and political subdivision of the state of Connecticut (“ Seller ”), and, solely with respect to Section 9.25 and Section 9.26 thereof, South Central Connecticut Regional Water Authority (“…

General Counsel — Carleton B. Simpson: The filing discloses the internal promotion of Carleton B. Simpson to Senior Vice President and General Counsel, which is a succession event rather than a departure.

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant The disclosure in

Regulation FD Disclosure A press release announcing the completion of Unitil’s acquisition of Maine Natural is attached as Exhibit 99.1 to this Form 8-K.

Entry into a Material Definitive Agreement 1. Credit Agreement On October 31, 2025, Unitil Corporation (“ Unitil ”) entered into a Credit Agreement dated as of October 31, 2025 among the following parties (the “ Credit Agreement ”): Unitil; The Bank of Nova Scotia, as agent; and The Bank of Nova Scotia, as lender (the “ Lender ”). The Credit Agreement has a borrowing limit of $86 million. Subject to certain notice requirements, Unitil may irrevocably reduce or terminate the unutilized portion…

Entry into a Material Definitive Agreement On August 14, 2025, Unitil Corporation (the “Company”) entered into an underwriting agreement (the “Underwriting Agreement”) with Wells Fargo Securities, LLC as representative of the several underwriters named therein (the “Underwriters”), pursuant to which the Company agreed to sell 1,393,355 shares of the Company’s common stock, without par value (“Common Stock”), at a public offering price of $46.65 per share (the “Offering”). In connection with t…

Entry into a Material Definitive Agreement On July 8, 2025, Bangor Natural Gas Company (“ Bangor ”), a natural gas distribution utility subsidiary of Unitil Corporation (the “ Company ” or the “ Registrant ”), entered into a Note Purchase Agreement with CoBank, ACB and United of Omaha Life Insurance Company (the “ Note Purchase Agreement ”) pursuant to which it issued and sold (i) $14,000,000 of 5.70% Senior Unsecured Notes, Series 2025A, due July 8, 2030 and (ii) $18,000,000 of 6.31% Senior…

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant The disclosure in