Today's biggest winners and losers in the stock market.

On this episode of Stock Movers:

- NextEra (NEE) agreed to pay about $67 billion in stock for Dominion Energy Inc. in the biggest power acquisition ever, creating a giant utility extending from Florida to the artificial intelligence data centers clustered in Virginia. The scope of the transaction underscores how the spike in AI-driven power demand is pushing the utilities sector to seek ever-greater size and clout. The deal would position NextEra as the dominant utility in a region that’s struggling to meet the surge in electricity consumption. Dominion shares rose 9.4% to $67.56 as trading closed in New York on Monday, while NextEra fell 4.6% to $89.04.

-Seagate (STX) shares fell 6.9% Monday in its worst one-day drop in nearly two months after management comments at a JPMorgan conference sparked investor fears that the company won’t be able to keep up with soaring demand for memory chips. The declines come after a blistering rally in the sector that’s spanned roughly eight weeks, boosted by solid earnings from megacap technology hyperscalers, a slew of deals for the cohort and investor enthusiasm in the risk-on trade as high demand for artificial intelligence infrastructure persists. The SOX gained nearly 60% from the start of April through a May 11 record high.

- Regeneron Pharmaceuticals (REGN) said a key late-stage melanoma study failed, adding to a series of challenges for the US biotech. Regeneron’s experimental drug fianlimab couldn’t beat Merck & Co.’s established cancer blockbuster Keytruda in the study, Regeneron said late on Friday. Another head-to-head trial of the Regeneron compound versus Bristol-Myers Squibb Co.’s Opdualag continues. The shares plunged in trading on Monday.