Grab was fined about $6.4 million while Uber was fined about $6.58 million by the Competition and Consumer Commission of Singapore.
Ride-hailing firm Grab will submit a written representation appealing against the consumer watchdog's decision on its acquisition of Uber's business.
The Competition and Consumer Commission of Singapore has determined that Grab's acquisition of Uber is an infringement of competition laws.
The Competition and Consumer Commission of Singapore has issued interim measures to stop Grab's acquisition of Uber in the South East Asian region.
Competition watchdog wants both firms, Grab and Uber, to maintain independent ops while it investigates their merger.
The Competition Commission of Singapore will be entering the second phase of its study of the ComfortDelGro-Uber alliance.
Singapore's anti-competition watchdog has found no evidence to suggest that petrol companies are colluding to set pump prices.