BEIJING –US fast-food giant Yum! Brands has officially applied for regulatory approval for its bid for a famed Chinese food chain in a bid to increase its foothold in the world's fastest growing major economy.

The owner of KFC and Pizzahut has submitted materials of its bid for hot pot restaurant chain Little Sheep Group to the Ministry of Commerce for anti-monopoly review, the ministry's spokesman Yao Jian said on Wednesday.

The ministry is studying the materials and will formally start the review process if the materials are complete, Yao said. The review usually lasts 30 days, but can be postponed to as long as 150 days.

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China's anti-monopoly laws require firms to get regulatory approval for acquisitions if two firms' combined global revenues exceed 10 billion yuan ($1.54 billion).

Last year, Yum's revenues in China hit 33.6 billion yuan, while Little Sheep garnered in nearly 2 billion yuan.

Yum! offered to pay HK$4.43 billion for a 93 percent stake in the Inner Mongolia-based hot pot restaurant on May 13.

Related: China's Little Sheep devoured by Yum!

If the deal is approved, Little Sheep will be de-listed from the Hong Kong stock exchange.

Little Sheep Group is one of the most successful homegrown food restaurant companies. It has 179 self-owned restaurants and 274 franchisees by the end of last year.