The search company apparently plans to say Thompson is stepping aside for personal reasons.

Thompson has been the focus of questions about a discrepancy in his IT credentials and in official documents that the company filed with the U.S. Securities and Exchange Commission.

Thompson's resume and the SEC filings say that the CEO has a college degree in computer science, but he does not have such a degree. The company called it an "inadvertent error" when questions about Thompson's background arose earlier this month, but industry analysts and critics have cast doubt on that explanation.

There was no immediate confirmation of the move from Yahoo.

Developing story. More to come.