Chinese state-owned conglomerates China Merchants Group and China Cosco Shipping Corp. are among the firms expressing interest in PSA International Pte’s minority stake in the ports business of Hong Kong’s CK Hutchison Holdings Ltd., according to people familiar with the matter.

PSA is seeking about $4 billion for its 20% share of CK Hutchison’s ports assets, the people said, asking not to be identified because the matter is private. PSA, owned by Singaporean state investment firm Temasek Holdings Pte, is working with an adviser as it fields preliminary interest in the stake, the people said.

The sale process has just kicked off and PSA is holding early talks with potential bidders including China Merchants, Cosco and other firms in the sector, the people said.

Discussions are preliminary and the firms could decide against making offers, they said. Representatives for China Merchants, Cosco, PSA and CK Hutchison didn’t immediately respond to requests for comment.

Billionaire Li Ka-shing’s conglomerate CK Hutchison counts businesses spanning ports, retail, infrastructure and telecommunications. It’s one of the world’s biggest container terminal operators and port services providers, with holdings in about 51 ports in 25 countries, its website shows.

Based in Singapore, PSA International operates more than 60 deep-sea, rail and inland terminals across 42 countries, according to its website.