High-speed Internet access company ExciteAtHome Corp. said on Monday two of its debt holders were demanding payment of $50 million in notes by Aug. 31, which would have a "materially adverse" affect on its liquidity and ability to fund operations.

The demand would be the latest blow to ExciteAtHome, which is controlled by telephone and cable-television giant AT&T Corp. . Last week, the Redwood City, California-based company said its former auditors had expressed concern about the company's ability to stay in business.

Shares of ExciteAtHome, which operates a popular but money-losing Internet content site and a high-speed Internet access service, fell 11 cents, or 20 percent, to 40 cents a share on Nasdaq.

A stock price below $1 a share leaves ExciteAtHome in danger of being delisted from Nasdaq. If that were to happen, the company would be in violation of the terms on $100 million of debt, which means the debt could be called for immediate repayment.

Promethean Investment Group LLC, which loaned ExciteAtHome half of that $100 million, previously said it would likely seek repayment if the stock did not recover. The notes were issued on June 8 in a private placement to two investment funds managed by Promethean.

The investment firm now contends that ExciteAtHome "breached certain representations" made when the notes were issued, ExciteAtHome said in a statement.

The Internet firm currently does not have enough cash to fund its business for the rest of the year, so a forced, early repayment of its debt could put it into bankruptcy.

ExciteAtHome said it disputed the assertion that it breached representations, and that the notes may now be declared due and payable.

ExciteAtHome has been hurt by the collapse in the Internet advertising business, which its content sites depend on for revenue.