Key Highlights

● Quanta closed at $552.44 on October 22 as power contractors sold off.

● MasTec, Dycom and Primoris all hit 52-week lows.

● Comfort Systems fell after hours despite revenue of $3.77 billion and a $17.81 billion backlog.

● Quanta builds transmission lines and substations, with data-center power a large part of its story.

Quanta Services (NYSE:PWR) sank on Thursday, October 22, 2026, closing at $552.44 as grid and power contractors fell out of favor on the S&P 500. The move was part of a wider selloff in engineering, construction and power names. Quanta issued no company news.

Quanta builds and maintains electric transmission and distribution lines, substations and other infrastructure for utilities, and data-center power needs have become a large part of its story. That made it a popular way to play AI-driven electricity demand. On Thursday, investors headed for the exits.

Peers hit 52-week lows

The selling was broad across the group. MasTec (NYSE:MTZ), Dycom (NYSE:DY) and Primoris (NYSE:PRIM) all hit 52-week lows. GE Vernova (NYSE:GEV) plunged and was among the weakest performers in the S&P 500. Vertiv (NYSE:VRT) and Eaton (NYSE:ETN) slid.

After the closing bell, Comfort Systems USA (NYSE:FIX), another contractor exposed to data centers, fell in after-hours trading despite strong results. Comfort Systems reported third-quarter revenue of $3.77 billion, up from $2.45 billion a year earlier, and earnings of $13.91 a share, compared with $8.25 a year earlier. Its backlog rose to $17.81 billion from $14.06 billion at June 30. A drop after numbers like those showed how cautious investors had become.

Why the mood changed

The trigger was the report from Meta Platforms (NASDAQ:META) on Wednesday evening. Meta narrowed its 2026 capital spending range to $135 billion to $145 billion and posted negative free cash flow of $2.12 billion, its first cash outflow in more than a decade, according to market data. Its spending commitments grew to about $825 billion, according to market data.

The worry for contractors is not that AI demand has vanished. It is that the companies paying for data centers may find the bill harder to finance. Nvidia (NASDAQ:NVDA)'s chief executive fed that debate when he said, "The demand of the capital is much greater than the availability of the capital."

Lam Research (NASDAQ:LRCX)'s supply-constrained guidance also hit chip stocks, and the Philadelphia Semiconductor Index had its biggest one-day drop since June 23.

Rotation into defensives

The S&P 500 fell 93.74 points to 7,663.43, its worst day since July. The Nasdaq Composite tumbled 694.00 points to 26,008.86. The Dow Jones Industrial Average edged up 11.89 points to 52,867.98, and the Russell 2000 gained 3.01 points.

The industrials sector ended slightly lower, held back by GE Vernova and other power names, even as railroads rallied. Union Pacific (NYSE:UNP) and CSX (NASDAQ:CSX) rose after earnings. Consumer staples had their best day since April 2025, and health care hit a record.

Quanta Looks to Hyperscaler Plans for Direction

Hyperscaler earnings will set the tone. Microsoft (NASDAQ:MSFT) and Alphabet (NASDAQ:GOOGL) report on October 28, and Amazon (NASDAQ:AMZN) reports on October 29. Their capital spending plans will be read closely by investors in grid and power contractors.

The Federal Reserve announces its policy decision on October 28. The 10-year Treasury yield fell back below a closely watched threshold for the first time since September 22 on Thursday, which helped rate-sensitive stocks such as homebuilders.

Investors will also watch how Comfort Systems trades in Friday's regular session after its after-hours drop, as a read on sentiment toward the contractor group as a whole.