Katsuyoshi Tanaka, the representative of Steel Partners Japan, is set to quit and establish a firm that will offer investment services in Japan, a source said.

Tanaka is starting a company called Prosperite Japan, according to the source, who declined to be identified because the information is private. Tanaka will leave Steel Partners at the end of February, the source said.

Masako Matsuoka, Tokyo-based spokeswoman for Steel Partners Japan, declined comment.

Tanaka, a former manager in the energy business development unit of Mitsubishi Corp., joined Steel Partners Japan in November 2006 as a managing director, according to a statement by Steel Partners at the time.

New York-based Steel Partners, run by investor Warren Lichtenstein, has made a series of takeover bids in Japan since 2003 and has urged companies, including brewer Sapporo Holdings Ltd., to increase returns. While the fund made money, its acquisition attempts have been thwarted as targets turned to defenses, including poison pills and friendly tieups.

In 2008, shareholders led by Steel Partners ousted the management of Aderans Holdings Co., marking the first success in the fund's quest to force changes at Japanese companies.