KEY POINTS
  • Symantec said the investigation will likely force it to delay the release of its annual report.
  • The company's earnings beat estimates, but its forecast was weaker than expected.

Symantec plunged 20 percent in extended trading Thursday after the security software company said its board is investigating concerns raised by an ex-employee and that the matter has been relayed to the SEC.

"The Audit Committee of the Board of Directors has commenced an internal investigation in connection with concerns raised by a former employee," Symantec said in a press release that included its fiscal fourth-quarter results. "The investigation is in its early stages and the Company cannot predict the duration or outcome of the investigation."