Nvidia's $177 billion drop was more than double what CrowdStrike and Palo Alto Networks gained combined

Nvidia alone shed $177.0 billion in market value on Monday — more than double the combined $76.1 billion that CrowdStrike, Palo Alto Networks and Fortinet added on the best days any of them had had in months. Both moves came from the same headline.

The catalyst

On Saturday, Anthropic chief executive Dario Amodei published an open letter, "We Must Pace the Frontier," arguing AI capability is advancing faster than the industry's ability to make it safe and calling for developers to deliberately slow down. OpenAI's Sam Altman responded on X with "I agree with Dario," and the essay circulated over the weekend ahead of Monday's open (Fast Company, Yahoo Finance). By the close, the reaction had split the market cleanly in two.

Cybersecurity's rally

$CRWD closed up 13.85%, adding $29.3 billion to reach a $241.0 billion market cap. $PANW rose 13.09%, adding $36.4 billion to reach $305.9 billion. $FTNT gained 9.04%, adding $10.4 billion (Yahoo Finance, Benzinga). The read: security software benefits either way, whether AI development slows down or races ahead unsafely.

The chip side of the trade

The stocks most directly tied to AI infrastructure spending moved the other way, and moved harder. $NVDA fell 3.36%, cutting $177.0 billion off its market cap by itself. $AVGO lost $82.4 billion (-4.77%), $MU lost $57.9 billion (-5.25%), $AMD lost $37.1 billion (-4.40%), $INTC lost $30.4 billion (-5.59%) and $LRCX lost $30.9 billion (-8.29%) (Fast Company, Yahoo Finance). Percentage losses ran even deeper further from the largest names: $TER fell 13.30%, $COHR fell 12.73%, $HPE fell 10.76%, $SWKS fell 10.29% and $LITE fell 9.92%.

The selloff reached beyond chipmakers into the hardware that supports them. Two of the day's largest percentage losers in Industrials were data-center power suppliers: $VRT fell 7.63% and $ETN fell 7.57%, helping push the whole Industrials sector to a $77.8 billion loss (-1.42%), the third-worst sector on the day. Networking-chip names $MRVL (-7.32%) and $MPWR (-7.39%) fell alongside them, all names whose businesses scale with AI data-center buildout rather than with chips themselves.

$GLW fell 13.70%, but that one has a second, separate cause layered on top: Corning disclosed a $2 billion at-the-market equity offering Monday, which 24/7 Wall St. and Yahoo Finance reported also dragged Coherent down 11% and Lumentum down 9% in its own right — a dilution story, not an AI-pacing one, even though it hit the same day and the same basket of stocks.

What it did to the sector

Technology was the S&P 500's worst-performing sector Monday even with CrowdStrike, Palo Alto Networks and Fortinet's rally counted inside it: down 1.44% cap-weighted, a $395.8 billion loss. Strip those three winners back out and the rest of the sector was down closer to $472 billion.

Communication Services led every sector, but not for a reason connected to the pacing debate: $GOOGL alone added $133.2 billion of the sector's $146.7 billion gain — over 90% of it — after TipRanks reported Alphabet is planning an AI data center in Lea County, New Mexico. That is its own story, running in parallel to the chip selloff rather than part of it.

The index

Across the full S&P 500, the cap-weighted change was -0.45%, a $312.7 billion loss in aggregate market value — smaller than technology's drop alone, because Communication Services, Healthcare and Consumer Staples moved the other way and offset some of it.