A fund of one is a tailored investment vehicle serving primarily one large LP—combining fund legal structure with negotiated economics and mandate specificity.

How it works

Instead of raising a commingled fund from many LPs, the GP and a single allocator establish a dedicated LP entity. Terms—fees, carry, investment scope, reporting, and co-invest rights—are negotiated bilaterally. Capital may flow through the vehicle into the GP’s main fund, into direct deals, or into a segregated portfolio managed by the same team. The structure gives the LP confidentiality, custom reporting, and sometimes lower fees than the GP’s flagship fund. For the GP, it secures a large anchor without broad marketing. Regulatory and tax treatment still follows private fund rules despite having one dominant backer.

Why it matters

• Founders: Capital from a fund-of-one may move quickly and carry strategic alignment from a single deep-pocketed LP—but decision paths can differ from a traditional partnership vote.
• Investors: Large LPs gain bespoke access; emerging GPs may use fund-of-one arrangements as a stepping stone before a flagship fundraise.

Common mistake

Confusing fund of one with a simple co-invest check. The vehicle may have ongoing management, multiple deals, and fund-style governance—not a one-off SPV for a single company.

Related ideas

Separately managed accounts, anchor LP side letters, co-investment rights, and bespoke mandate funds.