Material Agreement Form 8 K

Item 1.01

Entry into a Material Definitive Agreement

On December 11, 2024, F.N.B. Corporation (the "Corporation") completed its offering of $500,000,000 aggregate principal amount of its 5.722% Fixed Rate / Floating Rate Senior Notes due 2030 (the "Notes"). The Notes were sold to the public at a price equal to 100% of the aggregate principal amount of the Notes. The net proceeds to the Corporation from the sale of the Notes, after the underwriting discount, but before estimated transaction expenses, were $498,250,000. The Notes were offered pursuant to the final prospectus supplement dated December 4, 2024 (the "Prospectus"), to the base prospectus with respect to the offering from time to time of Common Stock, Preferred Stock, Debt Securities, Depositary Shares, Warrants, Purchase Contracts and Units dated August 30, 2024, forming a part of the Corporation's shelf registration statement on Form S-3(File No. 333-281868).

The Notes were issued under an indenture, dated as of February 24, 2020 (the "Base Indenture"), between the Company and Wilmington Trust, National Association, as trustee (the "Trustee"), as supplemented by a third supplemental indenture dated as of December 11, 2024 (the "Supplemental Indenture"), between the Company and the Trustee (the Base Indenture, as supplemented by the Supplemental Indenture, the "Indenture"). The Notes are not obligations of, and are not, and will not be, guaranteed by any of the Corporation's subsidiaries.

The Notes will mature on December 11, 2030 (the "maturity date"). During the period from, and including, December 11, 2024, to, but excluding, December 11, 2029 (the "fixed rate period"), the Notes will bear interest at the rate of 5.722% per annum. Interest will be payable semi-annually in arrears on June 11 and December 11 of each year, beginning on June 11, 2025 and ending on December 11, 2029 (each such date, a "fixed interest payment date"). During the period from, and including, December 11, 2029, to, but excluding, the maturity date (the "floating rate period"), the Notes will bear interest at a floating rate per annum equal to Compounded SOFR plus 1.93%, as determined by the Calculation Agent in the manner described in the Indenture. Such interest will be payable quarterly in arrears on March 11, 2030, June 11, 2030, September 11, 2030, and at the maturity date. Compounded SOFR for each interest period in the floating rate period will be calculated by the Calculation Agent in accordance with the formula set forth in the Indenture with respect to the Observation Period relating to such interest period.

Prior to December 11, 2029 (one year prior to the maturity date, the "Par Call Date"), the Corporation may redeem the Notes at its option, in whole or in part, at any time and from time to time, at a redemption price (expressed as a percentage of principal amount and rounded to three decimal places), equal to the greater of:

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(a) the sum of the present values of the remaining scheduled payments of principal and interest on the Notes to be redeemed, discounted to the redemption date (assuming the Notes matured on the Par Call Date) on a semi-annual basis (assuming a 360-dayyear consisting of twelve 30-daymonths) at the applicable Treasury Rate (as defined in the Indenture) plus 25 basis points less (b) interest accrued to the date of redemption, and

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100% of the principal amount of the notes to be redeemed,

plus, in either case, accrued and unpaid interest thereon, if any, to, but excluding, the redemption date.

Additionally, the Corporation may redeem the Notes at its option, in whole, but not in part, on the Par Call Date at a redemption price equal to 100% of the aggregate principal amount of the Notes, plus accrued and unpaid interest thereon, if any, to but excluding, the redemption date. The Corporation may also redeem the Notes at its option, in whole or in part, at any time and from time to time on or after November 11, 2030 (30 days prior to the maturity date) at a redemption price equal to 100% of the aggregate principal amount of the Notes being redeemed, plus accrued and unpaid interest thereon, if any, to, but excluding, the redemption date.

The Corporation intends to use the net proceeds from the sale of the Notes for general corporate purposes, which may include making investments at the holding company level, providing capital to support the growth of First National Bank of Pennsylvania and refinancing of outstanding indebtedness.

The foregoing description of the Notes and the Indenture does not purport to be complete and is qualified in its entirety by reference to the full text of the Indenture and the form of Note. The Base Indenture, the Supplemental Indenture and the form of Note are included herein as Exhibit 4.1, Exhibit 4.2 and Exhibit 4.3, respectively, and are incorporated herein by reference.

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A copy of the opinion of Reed Smith LLP, counsel to the Corporation, relating to the legality of the Notes is filed as Exhibit 5.1 hereto.