S&P downgrades 22 banks

A host of inancial stocks, which had helped boost stocks from their March lows, were downgraded today by Standard & Poor's today.

S&P lowered the credit ratings on 22 U.S. banks, including Wells Fargo (WFC), Keycorp (KEY), news, msgs) and PNC Financial Services Group (PNC), news, msgs).

The big downgrade was a big reason why financial stocks were so weak today.

Wells Fargo was down 5.4% to $23.09. Keycorp lost 7.8% to $5.46, and PNC Financial dropped 3.6% to $37.99.

"Financial institutions are now shedding balance-sheet risk and altering funding profiles and strategies for the marketplace's new reality," S&P credit analyst Rodrigo Quintanilla wrote in a note today.

"Such a transition period justifies lower ratings as industry players implement changes."

Ratings on five banks -- Carolina First Bank, Citizens Republic Bancorp (CRBC), Huntington Bancshares (HBAN), Synovus Financial (SNV) and Whitney Holding (WTNY) -- were cut to junk.

Carlina First is privately held; the others saw their shares fell at least 6% on the day.

S&P said it will hold a conference call on Thursday to discuss the downgrades.