Companies House is built to answer one question at a time: what does this filing say. It doesn't walk a group upward to its ultimate parent, or downward through every subsidiary. And the PSC regime it publishes only captures a person or company at 25% of the shares or votes, or with the right to appoint the board. Everyone below that line is invisible on the register you'd normally check.

Getting past that today means going company by company through Companies House, reading each confirmation statement by hand for the shareholders the PSC filing doesn't show, then checking the charges register, the Gazette and the insolvency register separately for anything adverse. For a group of any size, that's hours of work, repeated for every client, every counterparty and every renewal.

whatdotheyown.com reads the same public filings: the Companies House register, the PSC register, confirmation statements, the charges register, filed accounts, the Gazette, the Insolvency Service and HM Land Registry, and assembles them into one ownership tree that resolves upward to the ultimate owner and downward through every holding, in one view instead of a dozen tabs.

There's a use for this data beyond onboarding and diligence: the meeting itself. A fee-earner or relationship manager who walks into a pitch or a renewal conversation already knowing a prospect's full group structure, the people and companies connected to it, and what's registered against it, is working from more information than the person across the table expects them to have.

Take Grosvenor Estate Holdings. The free tree shows a corporate PSC above it, but the shareholder register beneath resolves to seven individual owners, among them the Duke of Westminster, sitting over fifteen further holdings. Naming that structure unprompted, or noting a director shared across two of a client's entities, or flagging a charge that's about to be satisfied, signals a level of preparation that a standard “tell us about your business” conversation doesn't. It's the same register data used for KYC and audit planning, read for a different purpose: knowing more about the company than it volunteered.

Today, whatdotheyown.com is something you open and search by hand, one company or person at a time. That's fine for a single check before a call. It isn't fine for a firm that wants this sitting inside the CRM it already runs on.

We're building a documented API and an MCP (Model Context Protocol) server so a firm can pull the ownership tree, the shareholder register and the risk layers straight into Salesforce, HubSpot or whatever else holds the client record, the moment that record is opened, instead of someone switching tabs to look it up separately every time. This isn't live yet: it's on the roadmap, not something you can turn on today.

None of this is abstract. Three mechanisms turn directly into revenue, or into cost avoided.

Faster onboarding. The time saved not doing the same due diligence work by hand goes straight back into fee-earner capacity: more clients taken on in the same month, without adding headcount.

Catching risk before signing. A charge that's about to crystallise, an insolvency case attached to a connected entity, or a PSC that doesn't match what a prospect represented at pitch stage, caught before the engagement letter rather than after, is the difference between routine due diligence and a bad-debt write-off or a professional-negligence exposure downstream.

Walking in better informed. A pitch or a renewal conversation where you already know more about a prospect's structure than they've told you plays out differently to one where you're taking their word for it. That's the same reason relationship managers research a client before a meeting at all, just with a fuller, verified answer than a quick search gives them.

We won't put a number on any of that, because we don't have one we could stand behind. What we can say is the mechanism is real: less manual work, fewer risks missed, and better-informed conversations, all pointed at what every persona above is already paid to deliver.