Should we build our own AI investment platform or use one?

The custom-build case sounds compelling on paper: total control, exactly the workflow the fund wants, no vendor dependency. In practice, funds that go down this path discover three uncomfortable truths within the first year.

First, the surface area is enormous. A private capital platform is not one product. It is fund structuring, LP onboarding, KYC and AML, deal sourcing, diligence, IC governance, portfolio monitoring, LP reporting, compliance and audit trail, integrated. Each area is a serious product in its own right.

Second, AI moves faster than most in-house teams can absorb. Model updates, evaluation frameworks, prompt engineering, retrieval infrastructure, guardrails and source attribution are a full-time discipline. Funds building in-house typically freeze on the first model they integrate and fall behind within twelve months.

Third, governance is harder than it looks. Decision provenance, tiered source attribution, versioned mandate criteria, immutable audit trails and jurisdiction-appropriate controls are the difference between a working prototype and something a fund can defend to an LP or regulator.

Reuben AI ships all of this as production infrastructure, updated continuously. The build-versus-buy question is answered the same way it is answered for cloud infrastructure: buy the commodity layer, keep the differentiation in the investment strategy itself.