S&P 500 Closes Marginally Lower as Investors Parse Mixed Signals from US-Iran Talks

Wall Street experienced a volatile trading session, closing near its opening levels. Oil price fluctuations dominated the day's market rhythm, with investors interpreting complex signals surrounding US-Iran peace negotiations. The S&P 500 index closed down less than 0.1%. The index nearly recouped all its losses after a statement that a planned strike on Iran had been called off because "serious negotiations" to end the conflict were underway. The Philadelphia Semiconductor Index fell 2.5%, with Micron Technology dropping 6% as investors focused on potential labor actions at its rival Samsung Electronics that could disrupt memory chip supply. NVIDIA declined 1.3% ahead of its earnings report scheduled for later this week. Microsoft posted the largest gain among the tech giants tracked, rising 0.4%. Regeneron Pharmaceuticals fell as much as 13% intraday after data showed trial results for one of its drugs fell short of expectations. Walmart, which is also set to report earnings this week, advanced 1%. Investors are seeking signals about the state of the consumer as prices for items like gasoline rise. Earlier on Monday, both the US and Iran stated they had rejected new proposals, deeming them insufficient for an agreement. A report indicated the White House called a proposal from Tehran, delivered via mediators, lacking in substantive improvements. Simultaneously, Iran stated US demands were unacceptable. The risk of a reversal in the strong fund flows that have propelled US stocks to record highs in recent weeks is increasing. "The recent pattern now requires greater tactical caution. Many of the fund flows that drove this rally now appear significantly more mature. Higher long-term rates are beginning to compete with stocks again." At the close, the S&P 500 index was down 0.1% at 7,403.05 points; the Dow Jones Industrial Average was up 0.3% at 49,686.12 points; the Nasdaq Composite Index was down 0.5% at 26,090.73 points; the Nasdaq 100 Index was down 0.5% at 28,994.37 points; the Russell 2000 Index was down 0.7% at 2,775.102 points.