The company that issued the check, Association of Certified Liquidators, said no one had ever before tried to cash a promotional check.

"We're going to have to check into this," said the association's president, Mitch Klass.

It all began in May, Mr. Combs said, when he decided on a whim to see if a bank would accept the "nonnegotiable" check. On May 22 the bank credited his account $95,093.35.

Mr. Combs said he waited three weeks, but the bank did not mention the error.

"I was having fun with it," he said. "I would call my bank for my bank account balance and hear it jingle, 'over $100,000.' "

So he withdrew the money and put it in a cashier's check, which he then stored in the bank's safe deposit box.

First Interstate has said it noticed the error on June 5, but Mr. Combs said he was not notified until June 22. In the meantime, the bank froze his account and the teller machine kept his bank card.