FNB CORP/PA/

Proxy Statement

Our Proxy Statement contains information relative to our 2026 Annual Meeting of Shareholders (Annual Meeting) to be held on Wednesday, May 6, 2026, beginning at 8:30 AM, Eastern Time (ET). This year’s Annual Meeting will be held in an interactive, virtual-only format through a live webcast. We will provide the webcast of the Annual Meeting atwww.virtualshareholdermeeting.com/FNB2026.

The Annual Meeting presentation will be available online during the meeting and, during the 30 days following the meeting, a replay of the meeting will be posted on FNB’s website atwww.fnb-online.com/investors. For further information on how to participate in the meeting, please see Accessing Our Annual Meeting and About Our Annual Meeting in Annex A of this Proxy Statement. This Proxy Statement also relates to any adjournment of our Annual Meeting. This Proxy Statement was prepared under the direction of the F.N.B. Corporation Board of Directors to solicit your proxy for use at the Annual Meeting.

Our Proxy Statement and proxy voting card became available on March 25, 2026, and on that date, we commenced the mailing and distribution of our Proxy Statement and the accompanying proxy card to our shareholders of record as of March 9, 2026. We will bear all the costs of preparing and distributing our proxy materials to our shareholders. We will, upon request, reimburse brokers, nominees, fiduciaries, custodians and other record holders for their reasonable expenses in forwarding our proxy materials to beneficial owners.

Summary