HONG KONG, May 11 (Reuters) - Chinese battery maker CATL

is launching its Hong Kong public offering on

Monday, aiming to raise at least $4 billion at an around 5%

discount to its domestic share price, three people with

knowledge of the deal said on Sunday.

CATL's Shenzhen-listed shares last traded at 248.27 yuan on

Friday.

The company has finalised investor briefings ahead of book

building, having secured around $2.6 billion from cornerstone

investors, the three sources said, declining to be named as the

information was not yet public.

Cornerstone investors include Kuwait Investment Authority

and China's oil major Sinopec, which committed $500

million each, and a vehicle under Hillhouse Investment which

committed $200 million, two of the sources said.

CATL did not immediately respond to a Reuters request for

comment.

The cornerstone investors did not immediately comment.

(Reporting by Kane Wu, Julie Zhu and Summer Zhen; Editing by

Emelia Sithole-Matarise)