(Corrects name in headline to Fortress from Fortis)
SINGAPORE, April 7 (Reuters) - PACC Offshore Services Holdings (POSH), part of the empire of Malaysia's richest man Robert Kuok, has roped in Hwang Investment Management Berhad and Fortress Capital Asset Management as cornerstone investors for its Singapore listing, which sources close to the matter said could raise about $400 million.
The two cornerstone investors would take up 85.6 million shares, according to the company's preliminary prospectus.
POSH operates a fleet serving offshore oilfields in Asia, Africa and Latin America.
Singapore is home to the world's two biggest rig builders, Keppel Corp Ltd and Sembcorp Marine Ltd, as well as smaller oil services companies such as Ezion Holdings Ltd.
The sources declined to be identified because the information has not been made public.
Bank of America Merrill Lynch, DBS Group Holdings Ltd and Oversea-Chinese Banking Corp Ltd are joint issue managers, bookrunners and underwriters. (Reporting by Saeed Azhar; Editing by Mark Potter)