"I truly don't have a clue of what is going to happen," said Hale, adding that First Mariner may be able to work something out with the investors.

Hale remains First Mariner's largest shareholder, although he has sold nearly 116,000 shares since early September for $118,401, according to regulatory filings.

Banking experts say it's unclear what might happen next. Other banks similarly have delayed interest payments for five years, and they, too, are just coming to the end of their deferrals, the experts said.

First Mariner might be able to renegotiate the interest or principal it owes with investors — although such a deal would be difficult, the banking experts said.

Another option is for the banking holding company to file for bankruptcy and then sell the bank, said Ely, the banking consultant.

"The bank doesn't fail; the holding company fails," he said.

First Mariner declined to comment beyond its statement.

A buyer only steps in if the bank has a good business model, Ely added. In the case of 1st Mariner, he said, the bank has relied too heavily on refinancings, and that's a business that's not likely to rebound soon.

Another alternative would be for the company to convince regulators that it has a plan to restore profits and capital, so that regulators allow the bank to pay dividends to First Mariner, which in turn, can make the interest payments, said Cliff Rossi, a finance professor at the University of Maryland, College Park. But, he conceded, that's an unlikely scenario.

"They are definitely in crisis mode," Rossi said.

First Mariner's problems go beyond the pending interest payments, Rossi added, describing the company as "a ship that's been torpedoed multiple times."

"The company has taken a hit during the crisis," he said, "and they have never been able to regain any kind of solid ground."