S&P 500 Plunges Up to 3.8% as Circuit Breaker Talk Erupts

Wall Street woke up Thursday to a bloodbath. The S&P 500 sank as much as 3.8%, and traders started eyeballing the market's emergency circuit breakers — the automatic halts that kick in when selling gets truly ugly. The index would need to fall another 3.2 percentage points from that low to trip the first one.

Under U.S. exchange rules, a 7% drop from the previous close — an S&P 500 level of 7,150.41 — triggers a 15-minute market-wide halt if it happens before 3:25 p.m. ET. A 13% slide, or 6,689.09 points, brings a second 15-minute pause. Hit 20%, at 6,150.89, and trading stops for the rest of the day. The first two thresholds expire at 3:25 p.m. ET; the 20% floor stays live all session. Nasdaq and other U.S. exchanges go dark right along with the S&P 500 names.

The timing couldn't be worse for President Donald Trump, who has long treated the market as a scoreboard. On Wednesday he posted on Truth Social that the market had just hit another record high — 91 in under two years — adding, quote, 'Your 401(k)s are through the roof.' He signed off with 'Record Setting All! President DONALD J. TRUMP.' By the time of this report, the S&P 500 still hadn't hit that first circuit breaker.

Wednesday's rally, fueled by sweeping Democratic midterm victories, had lifted the S&P 500 by 1.6% — its best day in three months — while the Dow Jones Industrial Average surged more than 1,500 points. Thursday erased all of it in one session, with tech absorbing the worst of the punishment. Around 11 a.m. ET, the Nasdaq Composite was down nearly 5% and the S&P 500 off 3.2%. Nvidia shed more than 6%, and the broader semiconductor index cratered nearly 11%.

The AI trade is suddenly looking shaky. Investors are gaming out whether Democratic wins mean tighter scrutiny of data-center construction, and they don't love the answer. 'We suspect there is going to be some scrutiny on this aggressive AI buildout,' Ipek Ozkardeskaya, senior analyst at Swissquote Bank, told Reuters.

The carnage spilled into crypto too. Bitcoin dropped below $76,000, surrendering its post-election bounce, with roughly $428 million in leveraged crypto long positions liquidated inside an hour, as Decrypt reported earlier. Beyond politics, traders are still chewing on stubborn inflation and a Federal Reserve that hasn't tipped its hand on rates. Friday's October employment report is the next big clue — and markets will be watching it nervously.