Meta Platforms' third-quarter earnings report triggered a selloff in large technology stocks, pulling the S&P 500 lower on Thursday, October 22, 2026, even as the majority of its constituents rose. The divergence highlights the disproportionate influence of mega-cap holdings on index performance, a structural risk that remains embedded in many broad-market portfolios.
On that day, 337 of the 497 tracked S&P 500 stocks finished higher, with only 159 declining and one unchanged. Despite this breadth, the index closed lower because its market-cap weighting gives excessive sway to the largest companies. One major S&P 500 index fund held 519 positions as of June 30, 2026, yet Information Technology accounted for 38.0% of net assets and Communication Services added another 9.7%.
The concentration is evident in the market capitalizations of the top names: NVIDIA is valued at $5.09 trillion, Apple at $5.07 trillion, Alphabet at $3.97 trillion, and Microsoft at $3.89 trillion. When these giants decline simultaneously, hundreds of smaller gainers cannot offset their impact. Meta Platforms, a $1.42 trillion company, served as the primary catalyst for Thursday's weakness.
Meta reported third-quarter GAAP diluted earnings per share of $3.83, missing the consensus estimate of $5.70 by 32.79%. The shortfall was driven by a $9.89 billion charge related to an August 2026 settlement with 52 state attorneys general over teen mental health litigation. Excluding that charge, earnings per share would have been $7.40. Revenue rose 26.1% to $64.60 billion, beating expectations, but total costs climbed 68% to $51.61 billion, narrowing the operating margin to 20% from 40%.
Meta shares fell 6.98% on Thursday to $648.85 and dropped another 0.96% on Friday to close at $642.62, resulting in a one-month decline of 13.64%. Market volatility increased as the VIX climbed to 19.03 on October 22, up 14.1% from the prior day. The benchmark S&P 500 ETF continued its slide on October 23, falling another 0.52%.
Weakness among other top performers compounded the index's decline. Over the past month, NVIDIA is down 6.45% and Alphabet is down 5.22%, while the S&P 500 benchmark ETF slipped 1.02%. Meta's financial outlook suggests continued pressure: the company missed earnings in the second quarter by 14.42% and has raised full-year 2026 expense guidance to $175.00 billion to $179.00 billion. Capital spending for 2026 is set at $135.00 billion to $145.00 billion, and third-quarter free cash flow was negative $2.1 billion.
The company's chief executive noted that its new AI model, Muse, is "very compute intensive to run" in the near term. Further youth-related litigation trials are scheduled in coming months, adding uncertainty to a stock that has historically seen a -13.16% average move on earnings misses compared to a 1.26% average on beats.