The giants of private investment risk seeing a tantalising prize slip from their grasp. Three of the biggest—Apollo, Blackstone and KKR—collectively oversee assets that have ballooned to $3trn, from $200bn in 2008. So far, they have had to raise the lion’s share of this from a select group of financial institutions and the uber-rich. Now they and their competitors have the mass market in their sights. They have launched a wave of funds designed to entice retail savers to invest in unlisted assets such as private equity, property and private debt.