Facebook and Zynga have amended an agreement that gave the games developer strong access to the social network’s one billion users.
Zynga is the developer behind Farmville, a game once mostly played on Facebook, which at its peak attracted 82 million players a month.
Zynga now has its own games platform, but players will no longer be able to share their progress on Facebook.
Zynga’s share price fell by 13% in after-hours trading following the news.
It is the latest blow for the company, which last month announced job cuts and studio closures.
The change, which will take place from 31 March 2013, ends Zynga’s ability to promote its Zynga.com platform on Facebook.
The move also means it will no longer be required to display Facebook advertising on its own site.