Sidley Austin, Ashurst and Freshfields Bruckhaus Deringer have scored key advisory roles on Japanese trading house Itochu Corp and Thailand’s Charoen Pokphand Group’s joint $10 billion investment in Chinese conglomerate Citic Ltd.

Itochu and CP Group plan to take a joint stake of 20 percent in Citic, increasing their exposure to the world’s second-biggest economy even as it slows from the blistering growth of the past decade.

The deal will take place in two stages, with Itochu and CP Group agreeing to buy nearly 2.5 billion shares in Citic for HK$34.4 billion in April this year, and a further 3.3 billion shares for HK$45.9 billion in October.

Ashurst is advising Itochu on the investment, led by Hong Kong office managing partner Robert Ogilvy Watson, while Sidley Austin’s Hong Kong partner Constance Choy is representing CP Group.

A Freshfields team headed by China chairman Teresa Ko and Beijing corporate partner Richard Wang is advising Citic Group and Citic Ltd on the deal.

The investment is the biggest ever by Itochu, and the largest ever made by a Japanese company into China.

The deal fits with Citic’s mission to broaden its investor base into the private sector as part of Chinese President Xi Jinping’s reforms to state-owned enterprises.

Citic completed a restructuring in August by injecting about $36 billion worth of assets into a Hong Kong-listed unit as part of this reform programme.