Sources close to Onex Corp. said that the firm is looking to put up US$4.5 billion for its next fund. The US$4.5 billion fund will make large capitalization investments across North America, three sources with knowledge of the plan said. Onex Corp. is Canada's largest buyout firm.

If the plan goes ahead, the new fund will be almost the same size as its previous fund. Onex Corp.'s previous fund ultimately collected US$4.7 billion.

Onex Corp.'s fourth fund is said to make equity investments of US$125 million to US$750 million per project, according to one of the persons. Onex vice president in investor relations Emma Thompson was not immediately available to comment on the fundraising plan.

Toronto-based Onex is competing with other private equity groups for investment capital in an aggressive fundraising market. The investors in the fundraising market had become more selective. According to Preqin Ltd., a London-based research company, about 1,958 private equity funds are attempting to raise a total of US$770 billion.