Key Highlights

● Intel fell to $92.07 in the regular session amid a broad semiconductor retreat.

● Third-quarter Revenue rose to $16.51 billion and adjusted Earnings of $0.52 beat the $0.40 consensus.

● Fourth-quarter revenue guidance of $15.0 billion to $16.0 billion fell well below expectations.

● The stock plunged in extended trading as Intel warned of a PC slowdown.

Intel (NASDAQ:INTC) slid with the rest of the semiconductor sector during Thursday's session, then plunged in extended trading after its fourth-quarter forecast fell well short of Wall Street's hopes.

A down day before the main event

Intel's Thursday came in two acts. In the regular session on October 29, the stock fell to close at $92.07, according to market data. There was no company news to explain the move. Intel was simply caught in a broad semiconductor retreat as the PHLX Semiconductor index snapped a four-day winning streak.

Chip stocks across the board cooled. Marvell Technology (NASDAQ:MRVL) sank on reported Takeover talks with Lumentum (NASDAQ:LITE), Micron (NASDAQ:MU) slid as memory names lost momentum, and AMD (NASDAQ:AMD) and Nvidia (NASDAQ:NVDA) drifted lower. The Nasdaq-100 fell to 29,402.51.

Then came the second act.

The guidance shock after the bell

Intel reported third-quarter results after the close, and the headline numbers were solid. Revenue rose to $16.51 billion, up strongly from a year earlier, and adjusted earnings of $0.52 a share beat the $0.40 consensus. Its Data Center and AI segment was a bright spot, with revenue jumping to $7.32 billion.

The outlook was a different story. Intel guided fourth-quarter revenue to $15.0 billion to $16.0 billion, well below the roughly $17 billion analysts expected. It forecast adjusted earnings of $0.25 a share, far short of the $0.43 to $0.44 consensus. The company also said it expects a slowdown in PCs to last through at least the first half of next year.

The stock plunged in extended trading. Estimates of the drop varied with the time stamp: one source had shares near $77.96, while another cited a deeper slide to around $71.63. A third report said the stock pared some of its losses later in the evening.

Reports also differed on whether third-quarter revenue beat or narrowly missed expectations.

The guidance trap

Intel's evening was a textbook example of a pattern repeating across this earnings season: beat the quarter, fall on the next one. Investors are looking past current results to forward guidance, and any shortfall is being punished harshly. According to market data, 253 S&P 500 companies have reported so far, and with most of them beating estimates, a strong quarter on its own has become the baseline rather than the exception.

Intel and Amazon (NASDAQ:AMZN), which also tumbled after hours, together pushed Nasdaq-100 futures lower in evening trading, according to market data.

AI costs in focus

The regular-session chip weakness had its roots in Alphabet (NASDAQ:GOOGL)'s results. Alphabet reported negative free Cash Flow of $9.07 billion and suffered its worst day since its 2004 IPO, erasing about $500 billion in market value. Media reports said the results "reignited concerns over mounting AI costs."

One market analyst said that "markets are no longer rewarding companies simply for investing heavily in AI."

Elsewhere, the market rotated rather than collapsed. More than 400 S&P 500 stocks rose, and the Russell 2000 gained 28.71 points to 2,859.22. Third-quarter GDP grew faster than expected and September PCE Inflation ran hot, keeping a December rate hike from the Federal Reserve in play.

What to watch

Friday's regular session will show how deep Intel's after-hours drop runs once full Volume returns. Investors will weigh the strength in the data center Business against the weak PC outlook and the gap between guidance and expectations.

The read-across to other chipmakers will also matter. Arm (NASDAQ:ARM) reports in early November, and any further signs of PC softness could ripple through the sector. On the macro side, Friday's Employment Cost Index and the Fed's December 8 to 9 meeting will shape appetite for tech stocks.