S&P 500's worst 2026 losers split between AI fear and old failures
The S&P 500 climbed 8.28% this year, yet ten constituents lost over 40% as investors aggressively repriced AI-displaced software firms and punished severe operational missteps.
The S&P 500 returned 8.28% in 2026, but beneath that aggregate gain lies a stark bifurcation. Ten index constituents lost more than 40% of their value. The destruction splits cleanly between companies threatened by artificial intelligence and those ruined by old-fashioned operational failures.
A broad selloff in enterprise software and consulting began in February following a new model release from Anthropic. Traders quickly dubbed the downturn the "SaaS-pocalypse." The market is actively repricing any business model vulnerable to AI automation.
Intuit exemplifies the trend, plummeting 55.27%. Its TurboTax product generates roughly a quarter of the company's revenue and profit, but the arrival of cheap AI tax tools threatened that dominance. In June, Goldman Sachs analyst Gabriela Borges slashed her price target to $276 from $519. Intuit responded by cutting 17% of its workforce, about 3,000 jobs, and reducing its TurboTax forecast. Its valuation collapsed from over $219 billion a year ago to roughly $88 billion.
Consulting giants suffered a similar fate as clients redirected budgets toward internal AI deployments. Accenture fell 45.21% after new client orders slipped to $19.3 billion from $19.7 billion. The company cut its sales growth forecast to between 3% and 4%, triggering an 18% single-day drop. Cognizant, Gartner, and The Trade Desk each lost between 44% and 55% as investors decided their services are easily replicated by AI.
Traditional pitfalls drove the deepest losses
Surprisingly, the two worst performers in the index had little to do with AI anxiety. CoStar Group fell 58.86%, making it the S&P 500's weakest stock. Its core business grew revenue 23% to $897 million, but aggressive spending on its Homes.com listings site yielded just $3 million in profit. CoStar warned the site will not cover its costs until 2029.
In February, hedge fund D.E. Shaw demanded CoStar quit or shrink Homes.com, arguing the move could unlock more than $10 billion in value. CoStar dismissed the campaign as "activism malpractice." Shareholders ultimately backed the board in June, but not before Nasdaq dropped the
