Rare co-founders Chris and Tim Stamper have left the company after more than 20 years with the acclaimed development studio.
The two, who founded the company with Joel Hochberg, left Rare in December to pursue other opportunities.
Taking over the day to day running of the company are studio director Mark Betteridge and Gregg Mayles, lead designer on Viva Piñata
"Chris and Tim have helped shape Rare into the world-beating renowned development studio that it is today and their impact on the videogame industry as a whole is well known," Microsoft said in a statement issued to consumer site 1Up.
"They are simply leaving to pursue other opportunities and we wish them luck in their future endeavours."
Microsoft acquired Rare back in 2002 for US $375 million (EUR 282 million), and it has since released Xbox 360 exclusive titles including Perfect Dark Zero and Kameo: Elements of Power. It's latest project, Viva Piñata, was released in December, but failed to enter the All Formats charts in the UK.
Rare's next title for Microsoft is the latest instalment in the Banjo Kazooie series. A recent interview with Gregg Mayles, who now takes on the role of creative director, can be read here.