Vitesse Semiconductor Corp. said Wednesday that it has fired three top executives including company co-founder and Chief Executive Louis Tomasetta following allegations that stock options might have been awarded inappropriately.

The three officials, which include Chief Financial Officer Yatin Mody and Executive Vice President Eugene Hovanec, were put on suspension by the Camarillo-based chip maker last month following news reports suggesting stock option grants might have been back-dated to take advantage of surges in the company’s stock price.

Vitesse shares dropped 20 percent on Wednesday to close at $1.48. The company, which has received a Nasdaq delisting notification because of the delayed filing of its most recent quarterly report, said it has expanded its internal investigation of the option grants to also review accounting practices that may have affected its cash position at the end of certain reporting periods.

Christopher Gardner and Shawn Hassel, who have been acting chief executive officer and acting chief financial officer, respectively, since the April suspensions, have been named permanently to those posts. Gardner was vice president and general manager of the Vitesse’s Network Products Division and earlier had been the company’s chief operating officer. Hassel has been and continues to be a managing director of Alvarez & Marsal, a financial restructuring firm.

Vitesse said it has a “conceptual agreement” with Silicon Valley Bank to adjust its credit facility, which has exceeded its borrowing limits. Vitesse also has hired an investment bank to obtain more financing.

“This has been a very challenging time for the company,” Chairman John C. Lewis said in a statement. “As a board, we have taken quick and decisive action that we believe is in the best interests of the Company and its shareholders … The board has complete confidence in the new executive team.”