US attorneys have warned that Facebook Credits may be in violation of America's antitrust laws.
The Credits have been mandatory for any games developed on the platform since July. Previously, developers were allowed to use their own virtual currencies.
Attorneys Derek Newman and Brian Strange claim that making Credits mandator may violate US antitrust laws, according to GamaSutra. Companies are forbidden from forcing customers to purchase unwanted products in order to receive the item they intended to buy.
The two lawyers have set up a website, Stop Facebook Credits, and accuse Facebook of using its position as market leading to force developers into using Credits and blocking out rival virtual currencies.
Facebook takes a 30 per cent cut on all user Credit purchases, while some previous virtual currencies charged less.
"Virtual currency companies, game developers and the entire social gaming community are paying higher prices and receiving fewer services," said Strange.