CMA PR24 water redeterminations
On 26 March 2026, the Competition and Markets Authority (CMA) published its final determinations for five water companies—Anglian, Northumbrian, South East, Southern, and Wessex—serving 7 million households with combined annual revenue of £5 billion.
The CMA confirmed £463 million in additional revenue for the AMP8 control period (2025–2030), representing 17% of what the disputing companies requested. The allowed rate of return for the appointed businesses increased from 4.03% to 4.20%. The increase in return for the wholesale businesses is from 3.97% to 4.20%.
These changes are expected to increase customer bills by 2.2% on average relative to the Ofwat final determinations, helping companies attract investment and meet legal obligations.
Oxera supported Anglian Water and South East Water throughout the redeterminations, providing analysis and advice on the methodology.
Our summary of the main changes in methodology for the cost of capital, base and enhancement cost allowances, and outcome delivery incentives is available to download below.
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Peter Hope, CFA
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