We ranked 12 all-star tech CEOs on how much they made (or lost) for shareholders this year

Mike Segar/Reuters

Behind every great company, there's a great leader. 

But not every great leader did so great this year.

Here's a look at how 12 all-star CEOs at publicly traded tech companies, from Alphabet to Yahoo, performed in 2015.

We calculated by comparing the company's stock-price gain from January 2, 2015, the first day of trading, to close of markets on December 30.

A higher number means a higher return for investors. 

Keep scrolling for the countdown.

No. 12: Yahoo CEO Marissa Mayer, -34%

Market cap: $32.15 billion
Stock price on January 2, 2015: $50.66
Stock price on December 30, 2015: $33.37
Percent change: -34%

Yahoo CEO Marissa Mayer is under attack from activist shareholders, who claim that she's mismanaged the company and needs to resign, even as top execs pack their bags and leave. It's a lack of confidence reflected in Yahoo's stock price, which took a big hit this year. 

No. 11: Oracle co-CEOs Mark Hurd and Safra Catz, -18%

Market cap: $155.66 billion
Stock price on January 2, 2015: $45.02
Stock price on December 30, 2015: $36.93
Percent change: -18%

Oracle founder and executive chairman Larry Ellison is a colorful guy who built one of the most valuable companies in tech. But under the day-to-day leadership of co-CEOs Hurd and Catz, Oracle has struggled to make a dent in the exploding cloud market, even as competitors like Salesforce and Microsoft circle to steal away market share. 

No. 10: IBM CEO Ginny Rometty, -14%

Market cap: $135.6 billion
Stock price on January 2, 2015: $161.31
Stock price on December 30, 2015: $139.32
Percent change: -14%

Like a lot of older tech companies, IBM has been having a hard time keeping up with the changes wrought by cloud platforms like Amazon Web Services, which reduce the need for IBM servers and software. Still, under Rometty's leadership, IBM has been working hard at making a credible cloud play of its own.