Blackstone Group is in the final stretch of raising what would be the largest private equity fund ever. Big funds, however, do not necessarily translate into big returns.

The private equity giant has capped its latest fund at around $25bn amid strong demand, according to people familiar with the matter. Collecting that would take the fund past the $24.6bn record set by Apollo Global Management in 2017. Others also are raising big funds: Advent International said earlier this month it had raised a $17.5bn fund, and software-focused Vista Equity Partners is raising a $16bn vehicle.