Countrywide Financial Corp said on Monday it had access to $186.5 billion of cash as of June 30, as the largest U.S. mortgage lender attempts to assure nervous investors it expects to survive a credit crunch that has claimed dozens of smaller rivals.

In a U.S. Securities and Exchange Commission filing, the Calabasas, California-based company said it was at midyear using $93.3 billion of its $283.6 billion of short-term liquidity, leaving $190.3 billion untapped. It listed $3.8 billion of long-term debt maturing within six months.

Countrywide said liquidity included $46.2 billion of highly reliable short-term financing, including commercial paper that companies often use to fund day-to-day operations.

They're big numbers, said Frederick Cannon, managing director at Keefe, Bruyette & Woods Inc in San Francisco. But it's important to put them in context of a company that funds $40 billion a month in mortgage loans. Countrywide will have to adjust production to ensure it matches liquidity available in the market. It may mean production will be constrained.

The filing was the second time in five days that Countrywide had tried to reassure investors about its finances. On August 2, Chief Financial Officer Eric Sieracki said Countrywide's liquidity planning remained highly effective.

Countrywide shares closed up $1.75, or 7 percent, at $26.75 on the New York Stock Exchange.

The shares have nevertheless slid 37 percent this year amid signs rising defaults among riskier subprime borrowers are spreading to borrowers with good credit, especially from loans made in 2005 and 2006.

Investors are shunning perceived risk, refusing to buy many mortgage securities and forcing lenders to keep more loans on their own balance sheets.

Lenders, in turn, are tightening loan standards, making it harder for some people to refinance and driving mortgage rates higher -- perhaps contributing to even more defaults.

The situation is so fluid as to make it extremely difficult to peg a valuation on Countrywide shares, Cannon said.

He rates Countrywide market perform.

Earlier Monday, American Home Mortgage Investment Corp, one of the 20 largest U.S. mortgage lenders and one which catered to borrowers considered better credit risks, filed for Chapter 11 bankruptcy protection.

There's always concern when the market is this volatile, said Philip Kibel, a senior vice president at Moody's Investors Service. We still feel Countrywide has solid liquidity.

Moody's rates Countrywide senior unsecured debt A3, a medium investment grade, with a stable outlook.

Countrywide on July 24 posted a 33 percent decline in second-quarter profit and slashed its 2007 earnings outlook. Chief Executive Angelo Mozilo said it might not be until 2009 when the housing market recovers from too many unsold homes, overstretched borrowers, rising rates and nearly unprecedented home price depreciation.

(Additional reporting by Dan Wilchins)