May 12 (Reuters) - U.S. not-for-profit healthcare

network Kaiser Permanente is planning to sell off large

private-investment holdings due to cash constraints, the Wall

Street Journal reported on Sunday.

Kaiser has been working with investment bank Jefferies

Financial Group ( JEF ) in recent months to sell up to $3.5

billion of private-fund stakes to secondary buyers, the Journal

said, citing people involved with secondary deals.

Kaiser is expected to offer a similar sized collection later

this year, according to the report.

Kaiser and Jefferies did not immediately respond to Reuters'

request for comment.

Kaiser is one of the largest U.S. medical employers with

over 24,000 doctors and 73,000 nurses. It operates with 40

hospitals and has over 618 medical offices, according to its

website.