Intel's data center business just grew almost 80% in a year. Its outlook for the fourth quarter is sending the stock toward its worst day in half a century, erasing more than $125 billion in market value Friday.

Intel (INTC) stock fell as much as 30% in early trading Friday after the chipmaker's forecast for the final three months of the year came in well short of Wall Street's expectations.

At its low, the stock was down more than on any day since at least 1973, according to Yahoo Finance calculations from Norgate Data closing prices going back to May 1973. The previous worst was July 5, 1974, when Intel fell nearly 30%. Its 26% plunge on Aug. 2, 2024, is now third.

A close below about $68 would make Friday Intel's worst day since 1974. Below about $64.50, it would be the worst on record.

The sell-off caps a wild year. Intel stock nearly quadrupled from the start of 2026 to its June 22 record. Even after Friday's drop, it's still up more than 70% this year, but it has given back about half its value since that peak.

The selloff is also costing Washington. Intel's drop has shaved about $10 billion off the value of the US government's 9.9% stake, which it bought last August at $20.47 a share. Even so, the stake is still worth about three times what the government paid.

It has also broken below the $80 zone that held at its July low, and it's on track to close below where it stood before April 24, when Intel had its best day since at least 1973, a gain of about 24%.

Intel has broken below the $80 floor that held through the summer, giving back about half its value since its June record. · Intel filings, Yahoo Finance

The quarter itself was strong. Intel topped estimates with adjusted earnings per share of $0.52, and data center revenue jumped to $7.3 billion.

The outlook is what broke the stock. Intel expects fourth quarter revenue of $15 billion to $16 billion, below the roughly $17 billion analysts expected, and earnings per share of $0.25 against forecasts of $0.43.

Intel filings, Yahoo Finance

The PC market is the problem. AI data centers are soaking up the world's memory chips, pushing up prices for laptops and desktops. Intel now expects PC shipments to fall about 12% this year and another 10% in 2027. An accident at its Israel factory will cost about $300 million in fourth quarter revenue on top of that.

Bernstein analyst Stacy Rasgon called the outlook "(in a word) terrible" and cut his price target to $75 from $110.

PC makers Dell (DELL) and HP (HPQ) slid too, adding to a tech stock rout that has hit Alphabet (GOOGL, GOOG) and Amazon (AMZN) after their reports this week.

Intel said the PC slump won't let up until memory supply and prices return to normal.