⚠ Two Markets, Two Sets of Rule-MakersHigh threat

Vistra (VST) — threat to the moat

Read the PUCT's filings and PJM's auction parameters more closely than any demand forecast.

A merchant generator's revenue is determined by market rules it does not write. In ERCOT those rules are set by the Public Utility Commission of Texas and the grid operator; in PJM by a stakeholder process under federal oversight. Both have rewritten the economics of Vistra's assets within living memory.

What regulators set, in numbersERCOT low system-wide offer cap$2,000/MWhTrigger for the low cap12 hours at the cap in 24PJM capacity sold by Vistra, 2025$793MPJM capacity bought by Vistra, 2025$566MVistra 10-K FY2025 (ERCOT market design; East segment capacity)
A generator can be right about scarcity and still not be paid for it, because the ceiling is an administrative decision.

The clearest current example is the price cap. ERCOT's system-wide offer cap falls to $2,000 per megawatt-hour once prices have been at the cap for twelve hours in a rolling twenty-four-hour period, under an Emergency Pricing Program approved by the PUCT, and the maximum point on the demand curve is reduced to the same level once a defined reference price is exceeded1.

That is a deliberate policy decision to limit how much a generator can earn in a scarcity event — the very events that justify holding dispatchable capacity through years when it earns little. A generator can be right about scarcity and still not be paid for it.

PJM's mechanism is different and no less consequential: capacity auction rules determine what a plant is paid simply for existing, and those rules have been revised repeatedly, each time moving hundreds of millions of dollars between owners.

Neither market is hostile to generators, and both are politically responsive to retail electricity prices in a way that puts a ceiling on generator profitability by design. Watch the PUCT's rulemakings and PJM's capacity auction parameters more closely than the demand forecasts.

References
  1. ReportedERCOT's system-wide offer cap falls to $2,000 per megawatt-hour once prices have been at the cap for twelve hours in a rolling twenty-four-hour period, under an Emergency Pricing Program approved by the PUCT, and the maximum...
    Vistra Corp. Form 10-K, FY2025, market discussion — "ERCOT is an ISO that manages the flow of electricity from approximately 83,707 MW of 2025 peak demand to approximately 27 million Texas customers, representing approximately 90% of the state's electric load"; "PJM is an RTO that manages the flow of electricity from approximately 160,709 MW of peak 2025 demand to approximately 67 million customers" across thirteen states and the District of Columbia; "if a less efficient natural gas unit is needed to meet demand, its offer price sets the market clearing price for all dispatched generation in that market, regardless of other units' offer prices"; prices "vary within different zones due to transmission losses and congestion"; under the PUCT-approved Emergency Pricing Program the system-wide offer cap temporarily falls to $2,000/MWh if prices have been at the cap for 12 hours in a rolling 24-hour period, and the maximum point on each ASDC is reduced to $2,000/MWh for the remainder of the calendar year once the Cost of New Entry reference price is exceeded — FY2025 · publ. February 2026 · source ↗
Sources
Generated September 23, 2026