Updated from 1:33 p.m. ET

Financial stocks were mixed in trading Wednesday, as investors weighed the Obama administration's mortgage relief plan against other news in the sector.

The

Obama plan

, unveiled in Arizona this afternoon, commits $75 billion to help up to 5 million borrowers refinance, and provides incentive payments to mortgage lenders in an effort to help up to 4 million borrowers on the verge of foreclosure.

Banks stocks began slipping after Obama began his press conference after noon.

Bank of America

(BAC) - Get Report

closed down 6.7% to $4.57.

Citigroup

(C) - Get Report

was down 4.9% to $2.91.

Wells Fargo

(WFC) - Get Report

shares were off 4.7% to $13.05.

Regional banks also were slipping.

PNC Financial

(PNC) - Get Report

closed 3.2% lower to $25.60.

Fifth Third

(FITB) - Get Report

shares were down 12% to $1.47.

The NYSE Financial Sector Index was recently down 0.5% to 2,651.

Financial guarantors were bucking the day's trend.

MBIA

(MBI) - Get Report

shares were soaring 29.6% to $4.51 after the bond insurer announced plans to split its municipal underwriting business from its riskier guarantees of shaky structured finance. Rival

Ambac Financial

(ABK)

was climbing 8% to $1.21.

This article was written by a staff member of TheStreet.com.