According to Woofun AI, the Nasdaq 100 Index established a leading position driven by a strong reversal in AI chip stocks, with the explosive surge of core names like SanDisk Corp. (SNDK.US) becoming a key anchor for restoring market sentiment that day. On Monday midday, U.S. stocks showed a notably divergent landscape, with fluctuations in macroeconomic data interwoven with the tug-of-war over policy expectations. The Nasdaq 100 Index surged 1.7%, the S&P 500 followed with a 0.7% gain, while the Dow Jones Industrial Average remained essentially flat. This rebound was a direct correction to the sharp market adjustment the prior week, when the Nasdaq fell more than 4% and chip stocks plunged nearly 10%. On the policy front, Federal Reserve Chairman Warsh remained cautious about next week's Federal Open Market Committee (FOMC) decision, declining to offer predictions, emphasizing that recent elevated inflation data has not changed his assessment of the economic situation, even though the market broadly expects rates to remain unchanged in October. The bond market responded accordingly, with the 10-year U.S. Treasury yield rising about 6 basis points to 5.14%, a sharp contrast to last week's decline of nearly 15 basis points. As of Monday midday, the S&P 500 rose 51 points to 7,711, the Dow slipped 6 points to 51,996, and rate-sensitive defensive sectors showed the weakest performance. Although the Nasdaq 100 gained 511 points to 29,699, it remained about 2.3% below its September closing level. The Russell 2000 rose 0.6% to 2,736. Notably, among the "Magnificent Seven," Amazon.com (AMZN.US) shares rose 4.9% to $262.32, demonstrating the resilience of large-cap tech stocks.

Woofun AI's compiled data shows that a deep breakdown of sector ETFs and individual stocks reveals structural shifts in capital flows. Among S&P 500 sectors, the Technology Select Sector SPDR Fund (XLK.US) led with a 2.0% gain, followed by the Consumer Discretionary Select Sector SPDR Fund (XLY.US) up 1.6%. Conversely, pressured by rising Treasury yields, the Utilities Select Sector SPDR Fund (XLU.US) fell 1.6%, the Real Estate Select Sector SPDR Fund (XLRE.US) dropped 1.2%, and the Health Care (XLV.US), Energy (XLE.US), and Financials (XLF.US) sectors each declined about 0.8%. At the ETF level, the VanEck Semiconductor ETF (SMH.US) surged 3.0%, and the iShares Expanded Tech-Software Sector ETF (IGV.US) rose 1.9%. As gold futures fell about 0.5% to approximately $4,160 per ounce, the VanEck Gold Miners ETF (GDX.US) dropped 1.3%, while the SPDR S&P Metals & Mining ETF (XME.US) edged up 0.7%. Among individual stocks, AI chips led the gains: Intel Corp. (INTC.US) rose 5.0% after JPMorgan (JPM.US) upgraded it to "Neutral," and Lam Research Corp. (LRCX.US) gained 5.4%. Memory chip stocks rebounded after last week's plunge: Micron Technology Inc. (MU.US) rose about 4%, SanDisk Corp. (SNDK.US) soared nearly 7%, and SK Hynix gained about 6%. In the optical chip space, Marvell Technology Inc. (MRVL.US) surged 7.3%.

Anomalous moves in special sectors and earnings-driven action further enriched the market picture. In the Russell 1000, Cleveland-Cliffs Inc. (CLF.US) shares skyrocketed 16.0% to $14.06, becoming the day's biggest winner. Its third-quarter adjusted earnings per share came in at $0.28, beating expectations of $0.21; adjusted EBITDA was $612 million. Management expects that figure to exceed $700 million in the fourth quarter and surpass $4 billion next year, attributed to a favorable steel pricing and production environment created by tariffs. Data center concept stocks recovered after last week's selloff over financing concerns: Applied Digital Corp. (APLD.US) rose 10.2% to $19.89, while TeraWulf Inc. (WULF.US) and IREN Ltd. (IREN.US) each gained about 6%. Semiconductor equipment stocks also performed strongly, with FormFactor Inc. (FORM.US) rising 8.4% to $113.78 and Teradyne Inc. (TER.US) gaining 6.6%. This rebound, driven jointly by better-than-expected fundamentals and sector rotation, marks the market refocusing on tech and industrial leaders with substantive earnings support after experiencing a short-term liquidity shock.