Investors who spread money evenly across the S&P 500 had a calmer week than holders of the cap-weighted index, as a Friday selloff in AI-linked giants pulled the headline benchmark down about 2%.
Equal weight vs. the megacap drag
The Invesco S&P 500 Equal Weight ETF (RSP) gained roughly 0.5% for the week, according to Yahoo Finance calculations, while the market-cap-weighted S&P 500 fell about 2%. RSP gives each constituent similar influence, so losses in Nvidia, Microsoft, and Apple do not dominate the return.
About 72% of S&P 500 stocks still finished the week higher even as the index closed lower, a split that shows how concentrated the recent rally had become.
What triggered the reversal
Friday’s slide came as oil prices climbed and investors questioned debt-funded AI infrastructure bets. CoreWeave shares fell about 12% and were down roughly 25% over five sessions; Reuters-linked market coverage noted its bonds trading at yields above 15% as holders demanded more compensation for risk.
The Nasdaq Composite lost about 4.5% for the week, erasing a breakout above summer highs. Chip names extended losing streaks, with the PHLX Semiconductor Index down for an eighth consecutive session in late-week trading.
Failed breakout worries chart readers
The S&P 500 had briefly pushed past 7,845 on October 6, clearing an August peak near 7,817. By Friday’s close the index sat back below that level, a pattern technicians call a bull trap when buyers who chased the breakout are underwater.
Dell and Hewlett Packard Enterprise, two of the index’s strongest performers since March, each dropped more than 20% in the week after tripling earlier in the year, according to Yahoo Finance’s tally of the biggest movers.
What index investors can do this weekend
401(k) holders who rebalance once a year may find their US stock sleeve overweight megacap growth after the AI run-up. Shifting a slice into an equal-weight fund or a small-cap index is one way to reduce single-theme risk without timing the market.
Short-term traders watching support levels note 7,800 on the S&P and 27,200 on the Nasdaq as repair zones cited in market commentary. Missing those levels on a closing basis could invite more volatility as third-quarter earnings season continues.
Oil and rates still loom
Higher crude prices can compress price-to-earnings multiples even when corporate profits hold steady. U.S. Bank strategists told reporters Friday that expensive oil tends to make investors less willing to pay up for long-duration growth stories—the same group that led the 2026 rally.
Next week brings retail sales and additional Fed speaker commentary. For now, the message in the tape is rotation: winners from the AI trade gave back gains while the average stock quietly advanced.