U.S. financial services and asset management firm Blackstone Group plans to raise its next global private equity fund three years after gathering about $18 billion from investors for its last pool.

The firm is expected to seek more than $20 billion when it starts marketing its eighth buyout fund later this year.

The buyout firm is returning to the market as investors pile into the asset class.

The buyout deal value rose 90 percent in the first quarter compared with the same period last year.