Key takeaways
- Sempra (counting Oncor), Exelon, Duke Energy, PG&E and Southern Company each serve about 9 million or more electric and gas customers.
- NextEra Energy, parent of Florida Power & Light, is the largest US utility by market value and has agreed to acquire Dominion Energy, with closing expected in the second half of 2027.
- SoCalGas is the largest gas distribution utility; Atmos Energy is the largest gas-only company.
- Record capital plans, driven by data centers and grid upgrades, make these companies some of the biggest infrastructure buyers in the country.
Investor-owned utilities serve most U.S. electricity and gas customers and are spending record amounts on grids, generation and pipelines. This list ranks the largest holding companies by the customers their regulated utilities serve.
The largest investor-owned electric and gas utilities
Ranked by combined electric and natural gas customers, using each company's latest reported figures (2025-2026). States are where the company's regulated utilities serve retail customers.
| # | Company | Customers | States | Notes |
|---|---|---|---|---|
| 1 | SempraSan Diego, Calif. · Oncor (80% owned), SoCalGas, San Diego Gas & Electric | About 12.4 millionElectric and gas | CA, TX | SoCalGas, with 5.9 million meters, is the largest U.S. gas distribution utility. Oncor delivers power to more than 4.1 million Texas homes and businesses. |
| 2 | ExelonChicago, Ill. · ComEd, PECO, BGE, Pepco, Delmarva Power, Atlantic City Electric | Almost 11 millionElectric and gas (T&D only) | DC, DE, IL, MD, NJ, PA | Six delivery-only utilities; it owns no power plants. |
| 3 | Duke EnergyCharlotte, N.C. · Duke Energy Carolinas, Progress, Florida, Indiana, Ohio and Kentucky; Piedmont Natural Gas | About 10.3 millionElectric and gas | FL, IN, KY, NC, OH, SC | 8.7 million electric and 1.6 million gas customers. Sold its Tennessee gas business to Spire in March 2026. |
| 4 | PG&EOakland, Calif. · Pacific Gas and Electric Company | About 10 million accountsElectric and gas | CA | About 5.5 million electric and 4.5 million gas accounts serving 16 million people. |
| 5 | Southern CompanyAtlanta, Ga. · Alabama Power, Georgia Power, Mississippi Power; Southern Company Gas (Atlanta Gas Light, Nicor Gas, Virginia Natural Gas, Chattanooga Gas) | About 9 millionElectric and gas | AL, GA, IL, MS, TN, VA | Electric utilities in three states and gas utilities in four. |
| 6 | CenterPoint EnergyHouston, Texas · CenterPoint Energy Houston Electric, CenterPoint Energy Indiana, Minnesota and Ohio gas | More than 7 million metersElectric and gas | IN, MN, OH, TX | Includes 2.9 million electric customers in the Houston area. |
| 7 | National Grid (US)Waltham, Mass. · Niagara Mohawk, Brooklyn Union Gas (KeySpan), Massachusetts Electric, Boston Gas | More than 7 millionElectric and gas | MA, NY | Serves more than 20 million people. Parent is London-based National Grid plc. |
| 8 | Xcel EnergyMinneapolis, Minn. · Northern States Power (Minn. and Wis.), Public Service Company of Colorado, Southwestern Public Service | About 6.1 millionElectric and gas | CO, MI, MN, ND, NM, SD, TX, WI | 3.9 million electric and 2.2 million gas customers. |
| 9 | NextEra EnergyJuno Beach, Fla. · Florida Power & Light | More than 6 million accountsElectric | FL | FPL calls itself America's largest electric utility, serving about 12 million people. Pending merger with Dominion Energy. |
| 10 | FirstEnergyAkron, Ohio · Ohio Edison, Illuminating Co., Toledo Edison, FirstEnergy Pennsylvania, JCP&L, Mon Power, Potomac Edison | About 6 millionElectric | MD, NJ, NY, OH, PA, WV | Ten electric distribution companies; Energize365 plan calls for $6 billion of grid investment in 2026. |
| 11 | American Electric PowerColumbus, Ohio · AEP Ohio, AEP Texas, Appalachian Power, Indiana Michigan Power, Kentucky Power, PSO, SWEPCO | 5.6 millionElectric | AR, IN, KY, LA, MI, OH, OK, TN, TX, VA, WV | Owns the largest U.S. transmission system; plans to invest $78 billion from 2026 through 2030. |
| 12 | Berkshire Hathaway EnergyDes Moines, Iowa · PacifiCorp, MidAmerican Energy, NV Energy | About 5.3 millionElectric and gas | CA, IA, ID, IL, NE, NV, OR, SD, UT, WA, WY | Privately held by Berkshire Hathaway; plans about $33.3 billion of capital spending in 2026-2028. |
| 13 | Con EdisonNew York, N.Y. · Consolidated Edison Company of New York, Orange & Rockland | About 5.2 millionElectric, gas and steam | NJ, NY | CECONY: 3.7 million electric and 1.1 million gas customers; O&R: 0.3 million electric and 0.1 million gas. |
| 14 | Edison InternationalRosemead, Calif. · Southern California Edison | About 5 million accountsElectric | CA | Serves about 15 million people across a 50,000-square-mile area. |
| 15 | WEC Energy GroupMilwaukee, Wis. · We Energies, Wisconsin Public Service, Peoples Gas, North Shore Gas, Michigan Gas Utilities, Minnesota Energy Resources | 4.8 millionElectric and gas | IL, MI, MN, WI | We Energies' very large customer tariff for data centers was approved in April 2026. |
| 16 | Eversource EnergyBoston, Mass. and Hartford, Conn. · Connecticut Light & Power, NSTAR Electric, Public Service of New Hampshire, Yankee Gas, NSTAR Gas, Eversource Gas of Massachusetts | About 4.4 millionElectric and gas | CT, MA, NH | 3.5 million electric and 0.9 million gas customers. Sold Aquarion Water on June 30, 2026. |
| 17 | PSEGNewark, N.J. · Public Service Electric and Gas (PSE&G) | About 4.3 millionElectric and gas | NJ | 2.4 million electric and 1.9 million gas customers; PSEG Long Island also operates the Long Island Power Authority's grid. |
| 18 | Dominion EnergyRichmond, Va. · Dominion Energy Virginia, Dominion Energy North Carolina, Dominion Energy South Carolina | About 4.1 millionElectric and gas | NC, SC, VA | 3.6 million electric and 500,000 gas customers. Agreed in May 2026 to merge with NextEra; closing expected in the second half of 2027. |
| 19 | NiSourceMerrillville, Ind. · NIPSCO, Columbia Gas (Ohio, Pennsylvania, Kentucky, Maryland, Virginia) | About 3.8 millionGas and electric | IN, KY, MD, OH, PA, VA | 3.3 million gas and 500,000 electric customers; $28.6 billion capital plan for 2026-2030. |
| 20 | CMS EnergyJackson, Mich. · Consumers Energy | About 3.7 millionElectric and gas | MI | 1.9 million electric and 1.8 million gas customers, serving 6.8 million Michigan residents. |
| 21 | DTE EnergyDetroit, Mich. · DTE Electric, DTE Gas | About 3.7 millionElectric and gas | MI | 2.3 million electric and 1.4 million gas customers; has signed data center agreements with Oracle and Google. |
| 22 | PPL CorporationAllentown, Pa. · PPL Electric Utilities, Louisville Gas and Electric, Kentucky Utilities, Rhode Island Energy | About 3.6 millionElectric and gas | KY, PA, RI, VA | $23 billion capital plan for 2026-2029. |
| 23 | AmerenSt. Louis, Mo. · Ameren Missouri, Ameren Illinois | About 3.4 millionElectric and gas | IL, MO | 2.5 million electric and more than 900,000 gas customers. |
| 24 | Atmos EnergyDallas, Texas · Atmos Energy (six divisions) | About 3.4 millionGas | CO, KS, KY, LA, MS, TN, TX, VA | Largest gas-only distributor in the list; more than $26 billion capital plan through 2030. |
| 25 | AvangridOrange, Conn. · NYSEG, RG&E, Central Maine Power, United Illuminating, Southern Connecticut Gas, Connecticut Natural Gas, Berkshire Gas | More than 3.4 millionElectric and gas | CT, MA, ME, NY | Owned by Spain's Iberdrola. |
| 26 | EntergyNew Orleans, La. · Entergy Arkansas, Entergy Louisiana, Entergy Mississippi, Entergy New Orleans, Entergy Texas | About 3.1 millionElectric | AR, LA, MS, TX | Retail electric customers; has signed hyperscale data center agreements in Louisiana. |
Sources: company annual reports, earnings releases, fact sheets and investor materials, 2025-2026. Counts are rounded and combine electric and gas customers; some companies report meters or accounts. Sempra includes 100% of Oncor's 4.1 million delivery points although it owns 80%.
What stands out
- Five companies serve about 9 million or more customers each: Sempra, Exelon, Duke Energy, PG&E and Southern Company.
- A megamerger is pending. NextEra and Dominion would form a utility with about 10 million customer accounts in four Southeastern states if regulators approve.
- Delivery-only utilities are big buyers too. Exelon, FirstEnergy, Oncor and CenterPoint's Houston electric unit own wires, not most of the power plants, so their spending goes to transmission, distribution, meters and customer systems.
- Capital plans keep growing. AEP plans $78 billion for 2026-2030, NiSource $28.6 billion and Atmos more than $26 billion, driven largely by data centers, grid hardening and pipeline replacement.
About the data
We list U.S. investor-owned utility holding companies, including privately held ones (Berkshire Hathaway Energy, Avangrid) and the U.S. arm of National Grid. Independent power producers such as Constellation, Vistra and NRG are not included because they don't run regulated utilities. Public power utilities and electric cooperatives have their own lists: see the largest public power utilities and largest electric cooperatives.
Selling to investor-owned utilities
- Start with the capital plan. Each company publishes a multi-year capital plan by utility and category. That shows where transmission, distribution, generation and gas spending will land.
- Watch rate cases and data center tariffs. Approved rate cases and large-load tariffs unlock spending. Follow them in our rate case and IRP tracker and data center power tracker.
- Get on the approved-vendor list. Supply chain teams run RFPs and supplier qualification, often with safety, insurance and supplier-diversity requirements.
- Reach the operating companies, not just headquarters. Engineering, operations and IT decisions are often made at the state utility level.
How KSG helps
We map the right engineering, operations, IT and supply chain contacts at each operating company and reach them with outreach tied to their capital plans. See our utilities practice.
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