The records
UK acquisitions tracker: the public records that show who bought whom
Updated
Four public records between them show most UK changes of ownership. None of them is a deals list; each has to be read for what it is.
Companies House: who controls a company
A UK company must record the people and companies with significant control over it, which includes holding more than 25% of its shares or voting rights. A buyer that takes a company over becomes its controller.
Source: People with significant control (PSCs) guidance
Companies House publishes those notifications as a live stream, so each new controller can be read as it is filed.
Source: Companies House streaming API: PSC stream
It also publishes the whole register as a free snapshot download.
Source: Companies House PSC snapshot download
For one company at a time, its filing history and controllers are on its own record.
Source: Companies House advanced company search
The CMA: larger mergers
The Competition and Markets Authority lists every merger case it opens, each naming the buyer and the target.
Source: CMA cases: mergers
It also publishes the outcome of every merger investigation as a data file.
Source: CMA merger investigation outcomes
The Takeover Panel: listed companies
For a bid for a company covered by the Takeover Code, the Panel's disclosure table lists each company in an offer period.
Source: Takeover Panel disclosure tables
The Gazette
Company notices in The Gazette record corporate events such as a company being wound up or struck off.
Source: The Gazette: company notices