CLEVELAND -- Responding to market speculation, National City said it has experienced no unusual depositor or creditor activity Monday.

The Cleveland-based regional bank said it has more than $12 billion in excess short-term liquidity.

Investors have been worried about the solvency of some banks amid the sharp downturn in the mortgage market. National City Corp. has been among those hit hardest by rising mortgage defaults. It recently raised $7 billion in cash to shore up its capital base.

The bank said the recent capital raise has helped it to maintain a strong capital ratio.

Shares of National City plunged $1.27, or 29 percent, to $3.15 before trading was halted.

Trading is halted briefly, usually an hour, when a company has important news to announce, or when there is a major imbalance between buyers and sellers.

National City has been among those hit hardest by rising mortgage defaults.