Pennon Group plc (LSE:PNN) shares fell 0.90% to 331.0p in the latest session, placing the water utility group among the notable decliners on the London market. The move comes after a financial year in which earnings recovered sharply, but returns remained slightly below target and environmental performance stayed under scrutiny.

The group owns South West Water and is operating in a new regulatory period. Investors are therefore focused on delivery against investment plans, environmental targets and the direction of water-sector reform.

Key Highlights

In its FY2025/26 results, Pennon reported underlying EBITDA up 55%, with underlying operating profit more than doubling to £326 million. Water tariffs rose 23% as the new regulatory period began, while underlying operating costs rose 8%.

The full-year dividend was 29.29p per share, increased in line with CPIH under the group's dividend policy.

Return on regulated equity (RoRE) was 6.7% on a real basis, slightly below the 7% target. Capital expenditure was £644 million, and the group raised £635 million of financing during the year.

For FY2026/27, management expects group EBITDA growth of around 5% to 10% and capital expenditure of £620 million to £700 million.

About Pennon Group plc

Pennon Group plc (LSE:PNN) is a UK water and wastewater group. Through South West Water, it supplies water and wastewater services in the south west of England, and it has also developed a smaller renewable energy business, Pennon Power.

Its earnings are largely driven by a regulated asset base, with allowed returns, customer bills and performance incentives set by the regulator for each five-year period. The current period, often described as AMP8, began in April 2025.

The group accepted the regulator's Final Determination early, providing funding certainty for the period. Pennon's dividend policy provides for a base dividend that grows with CPIH.

Why Is LSE:PNN Down Today?

The 0.90% decline to 331.0p comes against a mixed fundamental backdrop. Earnings have recovered strongly, but investors continue to weigh the group's debt, regulatory uncertainty and environmental performance.

Group-level debt was around 65% of regulatory capital value, while Water Group gearing was 61.8%. The scale of investment required means borrowing remains an important consideration.

RoRE of 6.7% was slightly below the 7% target, and the Water Group is expected to remain in a net penalty position on outcome delivery incentives in FY2026/27.

Therefore, even though profit has recovered, the market is likely to focus on whether performance incentives, financing costs and regulatory reform will support returns.

Key Reasons Behind the Downtick

The first factor is returns relative to target. A RoRE of 6.7% is slightly below the 7% target.

The second factor is environmental performance. Absolute pollutions fell by around one-third and normalised pollutions by about 53%, and storm overflow spills fell 17%, but the provisional Environmental Performance Assessment rating is one star.

Third, cost growth continues. Underlying operating costs rose 8%, and management expects depreciation to rise by up to 10% and financing costs by up to 15% in FY2026/27.

Another consideration is regulatory reform. Pennon has submitted just over £250 million of cost change claims to Ofwat, and the timing of reforms and decisions remains uncertain.

Finally, the pace of customer bill increases keeps affordability in focus for customers, regulators and policymakers.

Key Growth Catalysts

The most important catalyst is regulated asset growth. Capital investment of £620 million to £700 million is planned for FY2026/27, supporting growth in the regulatory asset base.

Earnings growth is expected to continue, with management guiding to group EBITDA growth of around 5% to 10% and revenue up by £50 million to £70 million.

Operational improvement is another factor. The group reported a 53% reduction in normalised pollutions and a 25% reduction in storm overflow spill duration.

Pennon Power offers diversification, with five behind-the-wire solar sites identified and being implemented.

Regulatory reform could also provide clarity. The chief executive expects a transition plan and the Clean Water Bill by year-end, and noted increased Defra staffing and the appointment of Dame Julia Black as senior adviser on water reform transition.

Risks

The most significant risk for LSE:PNN is regulatory and political change. Reform of water regulation could alter allowed returns, penalties or investment requirements.

Environmental performance is another risk. Incentive penalties and reputational pressure can follow if pollution and spill targets are not met.

Financing cost is relevant. With high gearing and a large investment programme, interest rates and credit conditions influence earnings.

Affordability is also relevant. Higher bills increase the importance of customer support, collections and public acceptance.

Finally, weather and demand can affect operations, including drought, storms and seasonal consumption patterns.

Valuation

The valuation of LSE:PNN is likely to be viewed through regulated returns, dividend growth and balance sheet capacity.

At 331.0p, investors are weighing a regulated business with a dividend policy linked to CPIH and earnings recovery against high gearing, a slightly below-target RoRE and an uncertain reform environment.

Reference points include the 29.29p dividend, RoRE of 6.7% and expected FY2026/27 EBITDA growth of 5% to 10%.

The key valuation debate is whether delivery and reform can support sustainable returns on a growing asset base.

What Investors Should Watch Next

The next key event is the half-year results for 2026/27, scheduled for 1 December 2026.

Investors should follow progress on environmental metrics, the outcome of the cost change claims and any detail on the transition plan and the Clean Water Bill.

Other points to monitor include capital expenditure, financing, gearing, Pennon Power implementation and bill affordability measures.

For LSE:PNN, the central question over the coming quarters is whether operational improvement and reform clarity can support returns in the new regulatory period.