Autodesk shares rose 6.5% on the disclosure. Starboard said in its suit that Autodesk, in "an apparent effort to prevent a proxy challenge," deliberately waited until that window had closed before disclosing to shareholders that it would delay its annual report and had launched an internal investigation into accounting irregularities and financial misreporting. "Manipulating corporate governance and disclosure obligations to give stockholders only one choice of directors effectively gives them no choice at all," Starboard said in its complaint, which was filed in Delaware Chancery court. Autodesk began probing irregularities around how it reported operating margin and free cash flow in early March. By March 8, Autodesk had informed the SEC of the probe, regulatory filings show. The company waited until April 1 to tell shareholders about the investigation, filings show, which was more than a week after the nominating window had closed.