The failure of Bank of New England Corp. and fast-approaching deadlines for repaying debt have shaken investor confidence in MNC Financial Inc., the region's biggest bank company, which has seen its already-depressed stock price nearly cut in half this week to close yesterday at an all-time low.

Shares of the Baltimore-based parent of American Security Bank and Maryland National Bank fell for the fourth consecutive day yesterday, down 50 cents to close at $1.87 1/2. MNC stock had traded as high as $23 a share in the past year, before a mountain of souring real estate loans and concerns over the company's ability to pay off its debt sent the stock price spiraling downward.

Analysts said the rampant selling of MNC stock, which finished last week at $3.37 1/2, was sparked by increasing concern over MNC's viability, an issue that was highlighted when the federal government seized Bank of New England late Sunday, protecting its depositors but wiping out the value of Bank of New England stock.

Both MNC and Bank of New England gorged on real estate loans in the 1980s, and both have been hard hit by the deteriorating real estate market.

"Everybody was waiting to see if {Bank of New England} would go under," said John Heffern, a banking analyst with Alex. Brown & Sons Inc. in Baltimore. "Watching those shareholders get wiped out was really unsettling."

Adding to investors' skittishness are impending deadlines for repaying debt. On Monday, MNC must pay $375 million to a syndicate of bank creditors led by J.P. Morgan & Co. On Tuesday, another $271 million owed to investors in MNC's long-term debt is due.

Although MNC has sold several subsidiaries to raise money, it does not have enough cash on hand to make both payments. It is possible, analysts said, that J.P. Morgan could extend the Monday deadline if it is convinced MNC is moving forward quickly with the sale of its prized credit card subsidiary, MBNA America Corp.

To help persuade J.P. Morgan, sources said, MNC has authorized Goldman, Sachs & Co. to move forward next week with presentations to investors that could lead to a sale of MBNA America stock to the public. MNC has been trying to sell the subsidiary privately, but interest has been limited by numerous factors, especially the size of the subsidiary, which is the fourth-largest bank card operation in the nation.

The cool reception by private bidders prompted MNC last month to file a statement with the Securities and Exchange Commission outlining initial terms of the stock offering. Sources said MNC will file a final prospectus today, authorizing the sale of 45 million shares for about $20 each. If the issue is fully subscribed, it would mean a cash infusion, before Goldman Sachs's fees, of about $900 million -- far less than the $1.5 billion analysts had estimated the credit card company was worth.

"They're walking a very thin line," said Frank J. Barcocy, an analyst with the capital market unit of Merrill Lynch & Co. in New York. "The survivability near-term of MNC is very much contingent upon a sale of MBNA."

Daniel J. Finney, spokesman for MNC, said the bank company has not abandoned a private deal but "is keeping its options open."

A draft of the prospectus said MNC Chairman Alfred Lerner and Progressive Co., Lerner's Cleveland-based insurance firm, have agreed to purchase up to 30 percent of MBNA if stock in the credit card operation is sold, sources said. MNC officials would not confirm whether Lerner still intends to make such a purchase, which would have to be approved by the Federal Reserve.

Sources said the possibility of a public stock offering would put pressure on the private bidders, which include General Electric Co.'s credit subsidiary and a team of NCNB Corp. and the Canadian Imperial Bank of Commerce. None of those firms would confirm its interest in the credit card operation.

One obstacle facing potential purchasers is the enormous amount of "goodwill" -- the amount they would pay over the value stated for MBNA on MNC's books. The existence of that goodwill would hurt the earnings of any buyer, a factor that bank regulators and rating agencies likely would frown upon.