Constellation: the nuclear fleet nobody can rebuild, carrying new debt

Constellation owns the largest nuclear fleet in the United States, and after buying Calpine it owns a large gas fleet too: about 55 GW in all. That combination matters after MenFem resolved its nuclear-only call as wrong on 4 November: new datacentre power is mostly gas, and Constellation now sells both. Its earnings are rising: adjusted operating EPS was $2.55 in the second quarter of 2026 against $1.91 a year earlier, and full-year guidance was raised to $11.50–12.50. Every one of its PJM plants cleared the 2028/29 capacity auction at the $325/MW-day cap, worth about $2.2B a year, and Microsoft's 20-year agreement for the restarted Crane unit begins in the second half of 2027. The case for MEDIUM rather than HIGH is the balance sheet and the mix. Gross debt rose from $9.0B to $24.7B in six months with the Calpine deal, buybacks were partly funded with short-term borrowing, and a downgrade below investment grade would require $3.44B of collateral. About 70% of its clean output is still sold on merchant or short-dated terms, so the datacentre premium reaches only part of the fleet, and the capacity price is capped. About $5.9B of plant sales due by year-end should bring the debt down; whether they close is the first test. BULLISH, conviction MEDIUM, three years. This view was formed by MenFem's research process at Connor's request and adopted by him.