US retail energy supplier

Constellation US

Headquartered in Baltimore, Maryland and listed on NASDAQ as CEG, Constellation is the largest competitive retail energy supplier in the United States, serving millions of households and businesses across 16+ states with electricity and natural gas plans. Spun off from Exelon in 2022, Constellation is also the country's biggest producer of carbon-free electricity, dominated by its nuclear fleet.

See Constellation plans Call 1-855-465-1244

Founded 1999 2+ million residential and small business customers Baltimore, MD 16 states served

Founded

1999

Years in the US market

Customers

2+ million residential and small business customers

Households served

Employees

~13,000 (parent group)

Workforce size

About

Who is Constellation?

Registered as Constellation NewEnergy, Inc. (a subsidiary of Constellation Energy Corporation), Constellation uses this legal name for state public-utility-commission filings and customer contracts. The trading name on bills is the shorter, more recognisable form.

The company is headquartered in Baltimore, MD, where it runs senior management, customer operations and regulatory liaison with state commissions.

Constellation was established in 1999. A longer track record means more years operating under state-commission rules and a wider history of customer feedback, billing and regulatory interactions.

Constellation is part of the Constellation Energy Corporation group, which provides shared governance, financial backing and a broader pool of expertise in wholesale-market trading, hedging and regulatory work.

Ownership & corporate

Who owns Constellation?

Legal name: Constellation NewEnergy, Inc. (a subsidiary of Constellation Energy Corporation)
Parent company: Constellation Energy Corporation
CEO: Joe Dominguez (CEO, Constellation Energy Corp)
Publicly listed: Yes (NASDAQ: CEG)
Main shareholders: Publicly traded; major institutional holders include Vanguard, BlackRock and State Street. Spun off from Exelon Corporation on 1 February 2022.
Headquarters: 1310 Point Street Baltimore, MD 21231

Service area

Where Constellation operates

Electricity

10 states

Natural gas

13 states

Service availability varies by zip code within each state. Eligibility depends on your local utility's deregulation status — check on Constellation's website with your zip code before enrolling.

Plan structure

What plan types does Constellation offer?

Fixed-rate

Lock in a unit rate for 6, 12, 24 or 36 months. The flagship Constellation residential product, available in every state served.

Variable / month-to-month

Wholesale-indexed rate that changes each billing cycle. No commitment, no early-termination fee — useful as a bridge before locking a fixed plan.

Green / 100% renewable

Same fixed-rate structure matched with Green-e certified RECs. Small per-kWh premium over the standard plan.

Nuclear-matched

Unique to Constellation: a plan matched directly with output from its US nuclear fleet — the largest carbon-free generator in the country.

Home services bundles

Add HVAC, plumbing or electrical-repair coverage to an energy plan. Marketed under Constellation Home Services.

Renewable content: Constellation's parent company is the largest producer of carbon-free electricity in the US, with ~90% of its generation from nuclear, hydro, wind and solar. Renewable retail plans use Green-e certified RECs sourced from US wind and solar farms.

See current Constellation plans & rates

Timeline

Constellation — key moments

1999

Constellation Energy is established as the parent holding company of Baltimore Gas & Electric (BGE) and its competitive retail and wholesale operations.
2012

Exelon Corporation acquires Constellation Energy in a $7.9 billion merger; Constellation becomes Exelon's competitive retail-energy arm.
2014

Constellation acquires Integrys Energy Services, expanding its competitive footprint in the Midwest and Northeast.
2022

Constellation Energy Corporation (CEG) is spun off from Exelon as a standalone publicly traded company on NASDAQ.
2024

Constellation announces a $1.6 billion deal with Microsoft to restart the Three Mile Island Unit 1 reactor under a 20-year power-purchase agreement.

Contact

Reach Constellation customer service

Constellation's customer service handles enrollment questions, billing, switching and complaints. Have your account number from a recent bill ready to speed up the call.

Have your Constellation account number from a recent bill ready to speed up the call.
For service outages or downed wires, call your local utility — not Constellation. The retail supplier never handles the physical grid.
State-specific lines: Texas residential 1-888-900-7052; Georgia residential 1-877-677-4355.
Online chat available 24/7 for billing and account questions via constellation.com.

Customer service

1-855-465-1244

Mon-Fri 8 a.m. - 8 p.m., Sat 9 a.m. - 5 p.m. ET

Constellation online account

Frequently asked

Constellation — answers to common questions

Constellation is regulated by the public utility commission in each state where it operates. Reliability is best judged against your own usage profile: read recent reviews, confirm the customer-service hours match when you actually need to call, and compare the unit rate against the utility's price-to-compare for your zip code.

Plans can typically be enrolled directly on Constellation's website or by calling 1-855-465-1244. Before signing up, always compare the unit rate (¢/kWh for electricity, $/therm for gas) against your utility's price-to-compare for your zip code.

You can switch your retail supplier at any time, though early termination fees (typically $50-$200) may apply if you are on a fixed-rate plan and within the contract term. Check your enrollment letter or Terms of Service for the exact figure. Switching back to your default utility supply is always free.