Vistra Corp. (VST)

Vistra sells power at market prices rather than at a tariff — a generator without regulated protection and without its ceiling.

The company owns gas, coal and nuclear plants, chiefly in Texas, and sells output into the wholesale market and directly to consumers. No regulator guarantees a return here: in a year of scarce capacity prices spike and profit lands several times above normal, and in a quiet year the opposite. Hence volatility unusual for a utility.

Nuclear units acquired from a competitor turned the company into one of the few suppliers of round-the-clock carbon-free power — precisely what data-centre operators want, and they will sign contracts for decades. That story is what re-rated the stock. Risks: gas prices, Texas weather, plant condition and how much future output is hedged. Vistra pays a small dividend and buys back heavily.