Material Event (Form 8-K)

On December 29, 2025, National Fuel Gas Company (the "Company") filed a prospectus supplement ("Prospectus Supplement") to its effective shelf registration statement on Form S-3(Reg. No. 333-273926)filed with the Securities and Exchange Commission (the "Commission") on August 11, 2023. The Company filed the Prospectus Supplement for the purpose of registering for resale up to 4,402,513 shares of the Company's common stock, par value $1.00 per share (the "Common Stock"), by the selling stockholders identified in the Prospectus Supplement (the "Selling Stockholders"). The Common Stock was acquired by the Selling Stockholders in the private placement financing described in the Company's Current Report on Form 8-Kfiled with the Commission on December 15, 2025.

In connection with the filing of the Prospectus Supplement, the Company is filing an opinion of its counsel, Lowenstein Sandler LLP, regarding the legality of the Common Stock being registered, which opinion is attached as Exhibit 5.1 to this Current Report on Form 8-K.