ERCOT Retail Electricity: Vistra Passes NRG as Concentration Eases

 The following content was supplied by Preston Ochsner, Founder & CEO, Ochsner Interests, Inc.. Energy Choice Matters did not verify any statements, and any views expressed are those of the author and may not necessarily reflect the view of EnergyChoiceMatters.com.

ERCOT Retail Electricity: Vistra Passes NRG as Concentration Eases

By Preston Ochsner, Founder & CEO, Ochsner Interests, Inc.

Vistra passed NRG as the largest parent company in ERCOT's competitive retail electricity market in 2025, with 22.8% of load against NRG's 22.7%. A year earlier NRG led by nearly two points.

The data comes from the U.S. Energy Information Administration's Annual Electric Power Industry Report, Form EIA-861. EIA released the final 2025 data on October 7, 2026, and it covers calendar year 2025. It also shows concentration easing. The five largest parent companies served 69.4% of competitive retail load in 2025, down from 71.6% in 2024.

In September 2026 we published an analysis based on EIA's early-release data and said we would publish updated calculations when the final data was available. This is that update.

The market itself grew. Retail providers in ERCOT's competitive areas served 343.7 million MWh in 2025, or 34.4 million residential customer equivalents (RCEs), up 6.7% from 2024. Commercial load rose 10.2% and industrial load 6.6%, against 2.8% for residential.

M&A Implications

The data has several implications for retail energy M&A. Commercial and industrial (C&I) load together grew about 8%, three times the residential rate. A broader group of suppliers is gaining market share. And the remaining 49 smaller parents account for just 2.9% of load, illustrating the market's long tail and potential for further consolidation.

Scale is one factor in valuation, but margins, customer retention, and the buyer's ability to integrate the business often carry more weight. We return to these points later in this analysis.

Vistra Overtakes NRG in Load, While NRG Retains Customer Lead

Vistra's retail brands, led by TXU Energy, served 7.838 million RCEs in 2025. NRG's, led by Reliant, served 7.794 million. The gap is about 44,000 RCEs, or 0.13% of the market's load. In 2024, NRG led by roughly 570,000.

The change was driven mainly by Vistra. Vistra's load grew 6.1%, with TXU's industrial sales accounting for about 90% of the increase. TXU's industrial sales rose approximately 4,100 GWh. NRG's load held within about 2% of its 2024 level.

The lead is by load only. NRG still serves more customers, 2.93 million to Vistra's 2.62 million, and it remains well ahead in residential load.

Market Concentration Declines as C&I Suppliers Gain Share

The two largest parents served 45.5% of load in 2025, down from 47.6% in 2024. The top five served 69.4%, down from 71.6%. The Herfindahl-Hirschman Index for the market fell from 1,440 to 1,354, so the decline extends beyond the largest names.

The decline in concentration partly reflects where the market grew. Commercial load rose 10.2% and industrial load 6.6%, compared with 2.8% for residential.

Much of that growth went to suppliers of large commercial and industrial load. BP, the third-largest parent at 13.7% of the market, grew 13.6% and serves fewer than 700 customers. Calpine grew 33.1%.

The HHI is the standard measure of market concentration. It is calculated by squaring each participant's market share and adding the results. The economist Albert Hirschman proposed it in 1945, and Orris Herfindahl developed it independently in a 1950 study of the steel industry. The U.S. Department of Justice and the Federal Trade Commission have used it in merger review since 1982.

Under the agencies' 2023 Merger Guidelines, a market with an HHI above 1,800 is highly concentrated. At 1,354, ERCOT's competitive retail market is below that level. Our calculation uses each parent's share of load and is not an antitrust market definition. The index measures how load is distributed among suppliers, and a lower score does not by itself mean a more competitive market.

Residential Is a Different Market

Residential load remains far more concentrated than the market as a whole. NRG holds 37.2% of it and Vistra 29.7%. Together they serve 66.8% of residential load, against 45.5% of total load.

Their combined share of residential load was about 68% in 2024. NRG serves 2.69 million residential customers and Vistra 2.17 million.

The Long Tail

The 24 parents serving more than 100,000 RCEs hold 97.1% of the market. The other 49 hold 2.9%, about 1.0 million RCEs combined.

Within that group, 18 parents serve between 20,000 and 100,000 RCEs. The remaining 31 serve fewer than 20,000 each and together hold 0.5% of the market. Vistra and NRG each serve more load than the 66 smallest parents combined.

The market is still broader than the traditional list of retail electricity providers. Walmart again ranks 16th on the load at its own stores.

Rank	Parent	2025 RCEs (thousands)	Share of load
1	Vistra	7,838	22.8%
2	NRG	7,794	22.7%
3	BP	4,692	13.7%
4	Shell	1,980	5.8%
5	Calpine	1,541	4.5%
6	ENGIE	1,527	4.4%
7	NextEra	1,432	4.2%
8	Constellation	1,279	3.7%
9	Just Energy	1,266	3.7%
10	Tenaska	976	2.8%
11	Mitsui	544	1.6%
12	Mothership	348	1.0%
13	Undisclosed (identity withheld by EIA)	345	1.0%
14	AP Gas & Electric	313	0.9%
15	Freepoint	240	0.7%

Current Retail Prices

The EIA data describes 2025. For current context, we also looked at offers in the Oncor (Dallas-Fort Worth) area on October 13, 2026. These are current prices, not 2025 data, and they change frequently.

Residential: on the state's Power to Choose site, 39 providers listed 46 fixed-rate plans with a 12-month term. The median price was 13.1 cents per kWh at 1,000 kWh of monthly usage, about $131 a month including delivery charges.

Small business: on the broker site ElectricityPlans.com, 12-month fixed quotes from Gexa Energy (NextEra), ENGIE, NRG, and AP Gas & Electric ranged from 5.87 to 6.21 cents per kWh. These are energy-only rates that exclude delivery charges, so they are not comparable to the residential prices.

What It Means for Retail Energy M&A

The final data supports the conclusion we drew in September 2026: a few very large parents, a long tail, and consolidation as a recurring feature of the market.

Commercial and industrial customers are driving much of ERCOT's retail load growth, creating acquisition opportunities beyond the largest residential suppliers. An acquisition is one way to add that load and broaden customer mix.

For independent retail energy companies, a combination can create value through greater operating scale, more efficient use of collateral, and access to broader wholesale supply relationships. Those benefits can make smaller platforms attractive acquisition targets.

Size still shapes the buyer universe. In 2024, we noted that four of the five largest strategic acquirers were generally looking for transactions above 100,000 RCEs. Buyer requirements change, so we would not assume that threshold still applies. For reference, 24 parents in ERCOT are that large today. Sponsor-backed platforms and aggregators also pursue smaller transactions, with particular emphasis on earnings quality, customer retention, and integration opportunities.

Scale alone rarely determines value. A 50,000-RCE commercial book with durable margins may be worth more than a 150,000-RCE residential book with high attrition. Margin quality, customer mix, retention, and hedge and collateral position determine how a buyer underwrites an opportunity, along with its fit for that particular buyer.

The full parent-level ranking behind this analysis is available on request.

What Changed From September 2026

In September 2026, we published an analysis based on EIA's early-release 2025 data. The final release changes several of those findings, including the identity of the largest parent company and the concentration of load among the leading suppliers. This analysis uses the final data and parent ownership as of December 31, 2025.

One difference is a matter of ownership dates. The final analysis assigns each retail provider to its parent as of December 31, 2025. Calpine is therefore reported separately from Constellation, which completed its acquisition of Calpine on January 7, 2026. With the two combined, the top five would hold 73.1% instead of 69.4%.

The analysis also carries a more precise label. Every provider in the data reports within ERCOT, so we now describe the market as ERCOT's competitive retail market instead of Texas.

Source and Method

Source: U.S. Energy Information Administration, Form EIA-861, final 2025 data (released October 7, 2026), with final 2024 data for comparisons. Market-share calculations by Ochsner Interests, Inc.

The analysis covers 91 retail power marketers reporting sales in ERCOT, grouped into 73 parent-level entities for market-share calculations. Load is expressed in residential customer equivalents, with one RCE equal to 10,000 kWh of annual usage. Percentages are rounded and may not sum exactly.

Parent ownership is as of December 31, 2025. Later changes in ownership are excluded. EIA withholds the identity of three industrial respondents; each is counted as a separate parent, so the market has at least 70 and as many as 73 parents.

Retail prices are current as of October 13, 2026, and are not part of the EIA data. Residential prices are from the Public Utility Commission of Texas Power to Choose plan listing. Small business prices are from ElectricityPlans.com.