Aug. 11 (Bloomberg) -- Downey Financial Corp. and Vineyard National Bancorp, California lenders battered by mortgage-related defaults, said they may not have enough capital to continue operations amid a surge in depositor withdrawals.

It isn't yet clear whether Downey will be able to meet its obligations, according to a regulatory filing today. Vineyard said in a filing that its capital levels ``cast significant doubt on our ability to continue as a going concern.''

Downey, based in Newport Beach, was one of the largest sellers of option-ARMs, which let borrowers defer part of the monthly mortgage payment and add it to principal. Vineyard has amassed $132 million in losses in the past three quarters, erasing more than seven years' profit as more builders default on loans for residential construction.

After IndyMac Bancorp Inc.'s July seizure by regulators, Rancho Cucamonga-based Vineyard saw a ``significant amount of customer withdrawals, thus affecting our liquidity,'' according to the regulatory filing today.

Vineyard declined 8 cents, or 4 percent, to $1.92 as of 4 p.m. today in New York trading, and has plummeted 81 percent this year. Downey Financial fell 14 cents, or 6.3 percent, to $2.10 in New York Stock Exchange composite trading today. The shares have lost 93 percent of their value this year.

Phone calls to Downey Financial Chief Financial Officer Brian Cote and Vineyard spokeswoman Terra Newcomer Hagel weren't immediately returned.

`No Assurance'

``There can be no assurance that we will be able to arrange for sufficient liquidity or to raise additional capital in time to satisfy regulatory requirements and meet our obligations as they come due,'' Vineyard said. ``Our regulators may take other and further action, including assumption of control of the bank.''

In California, households are foreclosing at 2.6 times the national average. Downey Financial said last month that the second-quarter loss was $258.9 million. It has had about $600 million in losses over the past year. Depositor withdrawals were ``elevated'' after the end of June, Downey Financial said today.

``In light of the current operating environment and Downey's recent quarterly losses, the holding company and the bank have been working closely with the bank's federal banking regulators,'' Downey said in the filing. The lender formed a committee to consider alternatives, including raising cash.

More money is coming in than is being withdrawn, Downey said. If ``elevated levels of net deposit outflows resume, the bank's usual sources of liquidity could become depleted'' and it might not be able to raise more money or find additional financing, the company said.

To contact the reporter on this story: Linda Shen in New York at lshen21@bloomberg.net

Last Updated: August 11, 2008 17:50 EDT