Apple Computer ( AAPL) has been notified of derivative lawsuits that make claims against current and former officers and directors with respect to the company's stock option grant awards.

Apple said in a release late Wednesday that the suits were filed in the U.S. District Court for the Northern District of California and the Superior Court for Santa Clara County.

Apple announced last week that it had discovered irregularities in issuing certain stock option grants and is conducting an independent investigation into the matter.

Apple said it is evaluating its response to the lawsuits.

In recent after-hours trading, the company's stock was off 15 cents, or 0.3%, to $56.85.