U.S. large-cap growth stocks remained near record highs despite a sharp rise in Treasury yields and broad weakness across equities. The 10-year Treasury yield reached 5.3420% intraday on September 30, its highest level in more than 24 years, and rose 54 basis points in September to 5.29%, its largest monthly increase in four years. The S&P 500 closed at 7,666.45 on October 1, 1.70% below its August 13 record of 7,798.99, while the Nasdaq Composite closed at 26,871.60, 1.37% below its September 22 record of 27,244.28. The Nasdaq-100 gained 3.3% in September even as the Russell 2000 fell 5.3%, the Dow declined 4.1%, 78% of S&P 500 stocks lost ground and nine of 11 large-cap sectors ended lower. Technology and communication services rose 4.5% and 4.3%, respectively, as AI-linked and mega-cap companies lifted the indexes. Earnings provided additional support: the S&P 500’s 12-month forward EPS estimate rose from 310 points at the start of the year to more than 400, with Shinhan Securities projecting 440 by year-end if revisions continue. AI-capital-expenditure-linked industries increased forward EPS by 107% and contributed 47% of the increase in total S&P 500 earnings, compared with 16% growth for industries unrelated to AI CAPEX. Analysts said high rates have not yet materially damaged earnings or AI investment, partly because U.S. corporate interest expense is 1.2% of sales, a record low, and Big Tech companies are investing to compete for market leadership rather than simply to exploit cheap financing. They warned, however, that persistent inflation, higher energy prices, renewed oil-price gains, heavy government and corporate debt issuance, tighter monetary policy and prolonged borrowing costs could eventually erode profits and widen the gap between large-cap growth and smaller companies.