aaiPharma ( AAII) shares fell before the open Monday after the troubled biotech company decided to delay the filing of its annual report because of what it recently described as "unusual sales."

The company mentioned the possibility earlier this month, when it announced the discovery of unusual sales involving two of its drugs and said it might have to make an adjustment in 2003 financial results. That triggered an investigation by a panel of independent directors and the withdrawal of 2004 earnings guidance.

Following the March 1 announcement, the company's shares plummeted as analysts downgraded the stock and even dropped coverage.

In a statement Monday, the company said "the independent inquiry is ongoing and neither the company nor the board will be commenting further at this time." aaiPharma said the filing date for its 2003 10-K form will be extended to March 30 from March 15.

The filing delay involving the sales issue is the latest blow to the company. In February, aaiPharma announced it had set aside a $15.9 million reserve against revenue in the fourth quarter of 2003 to account for products that are returned. Shortly after that, aaiPharma said its chief operating officer was leaving to become president of a startup drug company.

Shares fell 30 cents, or 3.1%, to $9.11 in premarket trading. Shares were at a 52-week high of $31.85 in early January.