Blackstone, the private equity group, has gained exclusive short-term access to the investor base of three of the largest US banks to promote the initial public offering of its new $850m (€714m) fund, the Blackridge Investment Corporation.

The fund will raise cash on the public markets to lend it to US corporates as mezzanine debt with the promise of high returns. Investor appetite is expected to be strong and will give private equity exposure to retail investors.