Microsoft CEO Steve Ballmer on Friday announced his retirement just a month after he directed a massive reorganization of the company.

The 57-year-old executive said he was taking the step in “the best interest of the company I love,” according to Financial Times.

He also said, “There is never a perfect time for this type of transition, but now is the right time.” The retirement is expected to be phased in over the next 12 months.

Some saw the move as reflecting a fall-out between Ballmer and Microsoft founder Bill Gates, who issued a statement that said the company was “fortunate” to have had Ballmer’s guidance for the past 13 years, but fell short of thanking him.

Last month, Ballmer had significantly reshuffled the organization in attempts to turn Microsoft into a “devices and services” company.

Neither the shareholders nor Gates appeared to be impressed.

The previous failures of the Windows 8 and the 40 percent decline in stock prices since Ballmer took over from Gates in 2000 were cited as part of the reason why the CEO chose to exit.

He also leaves as a wealthy man, as the Microsoft shares he holds are worth more than $11 billion.

By Kim Ji-hyun and news reports