U.S. investment fund Carlyle Group is studying around 300 Japanese businesses as part of its pipeline, a sign of the continuing boom in private equity deals in the country.

"We look at a lot of deals every day," Kazuhiro Yamada, co-head of the Japan buyout advisory team, said in an interview. "Even though competition is increasing, if you look at the number of potential deals, there are actually not enough general partners to do them," he said, referring to private equity firms and their executives.

Carlyle will probably announce another two or three transactions in Japan this year, Yamada said. The biggest challenge is having enough employees to oversee and manage the deals Carlyle wants to do, he added.