U.S. stocks closed lower for a third consecutive session on September 9 as escalating Middle East tensions drove oil prices higher and elevated long-term Treasury yields weighed on equities. The Dow Jones Industrial Average fell 405.41 points, or 0.76%, to 52,380.66; the Nasdaq Composite lost 0.63% to 26,253.34; and the S&P 500 declined 0.48% to 7,636.36. West Texas Intermediate (WTI), a U.S. crude benchmark, rose 3.25% to $96.05 a barrel for its seventh straight gain, while Brent crude climbed 3.4% to $101.21, above $100. The U.S. Central Command said it attacked five crude oil tankers near Kharg Island, Iran's key oil export hub, and in the Gulf of Oman on September 8. Iran reportedly launched retaliatory strikes, leaving shipping through the Strait of Hormuz, a major energy chokepoint, without a clear path toward normalization. The U.S. Treasury Department raised the maximum size of its long-term bond buyback operation scheduled for September 10 to $6 billion, or approximately ¥920 billion, but some investors had expected $7 billion to $8 billion. The disappointment accelerated bond selling, pushing the 10-year Treasury yield briefly to 4.85%, its highest since November 2023, while the 20-year yield reached its highest since late August and the policy-sensitive two-year yield briefly rose to 4.43%, its highest since July 2024. Higher yields and inflation concerns spread selling across equities. Alphabet, Boeing and Procter & Gamble fell, while Chevron gained 1.9%. The Philadelphia Semiconductor Index rose 0.5%; SK Hynix's American depositary receipt (ADR) surged 7.5%, and Intel gained 1.69%, while Nvidia and Broadcom declined. Meta Platforms jumped 6.5% after announcing a consumer AI agent service on September 8. Cloudflare rose 10.6%, whereas ServiceTitan plunged 29.1% and Braze dropped 20.7%. New York Stock Exchange volume was 1.1679 billion shares, down 54.07 million from the previous session. Market participants increasingly see prolonged Middle East hostilities as a source of further energy-driven inflation that could limit the Federal Reserve's scope for monetary easing. Bond-market developments and the trajectory of the Middle East situation are expected to remain key near-term focal points.