The U.K. Competition and Markets Authority said Oct. 16 that it has launched its phase 1 investigation into Amazon.com Inc.'s minority investment in Roofoods Ltd., which operates as Deliveroo.

Amazon led a $575 million funding round in Deliveroo in May.

The CMA previously ordered Amazon and Deliveroo to halt any attempt of integration until it decided whether to investigate the deal. The regulator has said it had "reasonable grounds" to suspect that the two companies "have ceased to be distinct," or were considering arrangements to that effect.

The competition regulator expects to announce a decision on the first phase of its investigation on Dec. 11.