Britain referred to Facebook's acquisition of the Giphy website for an in-depth investigation after the American social media giant told the country's competition watchdog that it would not make any pledges to address its concerns, according to Reuters.
The regulator last week gave Facebook and Giphy five working days to submit proposals to address their concerns about the merger deal, which could affect digital advertising and the provision of motion pictures.
The UK Competition and Markets Authority launched a preliminary investigation in January at a time when the US-based social media company was under global regulatory scrutiny over antitrust concerns.
It found that Giphy, which was once a competitor to Facebook in digital advertising through paid sponsorship outside the UK, has plans to expand sponsorship deals to other countries, including the UK.
The regulator said: If Giphy and Facebook continue to be merged, Giphy may have less incentive to expand its digital advertising.
The world's largest social media company bought Giphy, a website for creating and sharing gifs or GIFs, in May last year to combine it with the fast-growing photo-sharing app Instagram, however.