Largest Utility Companies by Market Capitalization

Approximately 607 publicly listed utility companies operate worldwide, but the sector is heavily concentrated at the top — the ten largest constituents make up roughly 59% of the utilities slice within the S&P 500. Under the GICS classification developed by MSCI and S&P, the utilities sector covers electric, gas, and water utilities as well as independent power producers and renewable electricity generators.

Electric utilities account for about 65.7% of the sector, followed by multi-utilities at 26.7%. The remainder is split among gas utilities, water utilities, and independent power producers. Leading names span several countries and sub-industries:

• Regulated electric: NextEra Energy (NEE), The Southern Company (SO), Duke Energy (DUK), American Electric Power (AEP) — all listed on U.S. exchanges. NextEra is also one of the world’s largest solar and wind power operators.
• Diversified electric: Iberdrola (IBE), headquartered in Spain and formed through a 1992 merger, serves more than 36 million customers across Europe, the Americas, and beyond.
• Hydroelectric power: China Yangtze Power, listed on the Shanghai Stock Exchange, manages the 22.5-gigawatt Three Gorges Dam — the world’s largest hydropower plant.
• Transmission & distribution: National Grid (NGG), based in London and also listed on the NYSE, handles electricity and gas transmission across the UK and parts of the U.S.

The United States is home to the largest concentration of listed utility companies, with over 110 publicly traded firms. Regulated utilities operate under a distinctive model: they receive monopoly rights in their service territories, but rates and capital plans must be approved by government regulators. High capital expenditure is a permanent feature, as these companies continually invest in power plants, pipelines, solar installations, and water-treatment facilities.

Popular ETFs tracking utility stocks include the Utilities Select Sector SPDR Fund (XLU), Vanguard Utilities ETF (VPU), and iShares U.S. Utilities ETF (IDU).

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The following table contains a list of the largest publicly traded utility companies by market capitalization across global exchanges, covering integrated electric utilities, gas distributors, multi-utilities, and renewable energy operators. Prices and market cap figures are updated regularly to reflect current market conditions.