The industrial companies selling fiber, turbines, cooling systems and grid labor to the AI buildout led the market for most of 2026. But now, they are leading it lower.
A Democratic sweep of Congress last week turned a slow leak into a rout. The wins included Republican strongholds and the key data center hubs of Texas and Georgia, raising the prospect of greater scrutiny for industries that benefited from GOP control.
GE Vernova Inc. (GEV) fell 9.3% the day after the elections, while Constellation Energy Corp. (CEG) and Vistra Corp. (VST), two power producers heavily exposed to Texas data center projects, slid 6.7% and 13.8%. Vertiv Holdings Co. (VRT) dropped 13% the same day on fears of data center moratoriums.
The damage spread the next session when the Philadelphia Semiconductor Index plunged 12.3% on Nov. 5, its worst day since March 2020, and the Nasdaq fell 5.5% to confirm a correction. The Dow lost about 1,800 points.
The Run-Up Set the Trap
The past 30 days wiped out a big slice of the year's gains. Corning Inc. (GLW) fell 12.9% on Nov. 5 to $103.43, leaving the stock down 35.1% over the prior month. The fiber maker had a long way to fall. Its shares rose 84% in 2025 on demand from AI data center construction.
Siebert Financial CIO Mark Malek framed the changing tide as the industry's new reality.
"The AI buildout will become more expensive, not disappear," Malek told Reuters. Most analysts doubt legislation could meaningfully stall construction, but a Democratic Congress raises the odds of more hearings, investigations and delays.
Caterpillar Inc. (CAT) lost 29.7% in the month through Nov. 6, while the S&P 500 fell 4.9%. Earnings day did much of the damage. Shares sank 9.3% on Oct. 29, their worst day since at least the start of 2025, after the company beat third-quarter estimates but held its annual sales forecast, and its record $78.1 billion backlog missed bullish hopes of $80 billion.
The rest of the group followed. Vertiv fell 28.3% from Oct. 7 to Nov. 5, and Eaton Corp. plc (ETN) dropped 24.2% over the same stretch.
GE Vernova slid 15.9% in the month through Nov. 4, and Quanta Services Inc. (PWR) fell 14.2% from its Oct. 2 close to Nov. 4.
Buyers finally stepped in on Monday. Corning closed up 9.25% and Caterpillar gained 7.21% on Nov. 9, according to market data.
GLW, CAT Price Action: Corning shares were down 1.7% at $114.00, and Caterpillar shares were down 3% at $580.64 in early trading Tuesday, according to market data.
