Not all newly minted CEOs can hit the ground running like Apple chief Tim Cook, who celebrated one year on the job Friday.

Robert Hum, stat man for CNBC, looked into the stock performance of other notable newbie chiefs to see how they stand up against Cook’s 76 percent gain.

Here’s the back-of-the-envelope performance since they started: Google’s Larry Page: +15 percent. Marissa Mayer at Yahoo!: -5 percent. Ex-Apple exec Ron Johnson at JCPenney: -23 percent.