(Reuters) - U.S.-based investment firm Carlyle Group ( CG ) has entered India's auto components market by buying a controlling stake in an entity formed by the combination of Indian auto parts companies Highway Industries and Roop Automotives.

Equity for the investment will come from funds affiliated with Carlyle Asia Partners, the firm said on Wednesday without disclosing any financial details.

Highway Industries is a manufacturer of powertrain parts and subsystems. Roop Automotives produces steering yokes and exports them to Europe and North America.

The founders of both the Indian firms will continue to hold stakes in the merged platform, Carlyle said.

The size of the deal is about $400 million, where Carlyle will own 65%-70% stake in the platform, the Economic Times reported citing sources.

On January 7, India's competition regulator gave its nod to a transaction that constituted a securities swap between Highway and Roop, and a 68.9% stake buy in Roop by Carlyle.

(Reporting by Adwitiya Srivastava in Bengaluru; Editing by Mrigank Dhaniwala)