Quintus shares plunged $3, or 50 percent, to a 52-week low of $3 after the software developer said it was delaying its 10-Q filing so that an outside auditor can review its financial information.
Quintus (Nasdaq: QNTS) also said it was placing CEO Alan Anderson on administrative leave.
The company said it was delaying filing its 10-Q for the second quarter to look into whether the payments it received from an outsourcing company, announced in a statement on October 17, "were in fact paid by or on behalf of the outsourcing company."
PricewaterhouseCoopers will be in charge of the audit and chief operating officer Paul Bartlett will serve as acting chief executive officer.
In its latest quarter, Quintus missed analysts' estimates when it posted a loss of $3.5 million, or 9 cents a share, on sales of $21.4 million.
First Call Corp. consensus expects it to lose 6 cents a share in its third quarter and 19 cents a share in the fiscal year.
The stock moved as high as $59.25 in December before falling to a new low Wednesday.
All three analysts following the stock rate it a "buy."