1 [LETTERHEAD] EXHIBIT 23.6 ALEX SHESHUNOFF & CO. INVESTMENT BANKING November 12, 1997 CONSENT OF ALEX SHESHUNOFF & CO. INVESTMENT BANKING In connection with the proposed merger of West Coast Bank and F.N.B. Corporation, the undersigned, acting as an independent financial advisor to the common shareholders of West Coast Bank, hereby consents to the reference to our firm in the Form S-4 Registration Statement and to the inclusion of our fairness opinion as an exhibit to the S-4 Registration Statement. ALEX SHESHUNOFF & CO. INVESTMENT BANKING