Update: US Equity Indexes Drop as Sharp Sell-Off in Semiconductor Heavyweights Sinks Technology While Crude Oil Surges

03:39 PM EDT, 10/08/2026 (MT Newswires) -- (Updates with index/price moves and geopolitical news from the first paragraph.) US equity indexes fell as a sell-off in semiconductors pushed technology to the bottom of sector charts, while crude oil surged ahead of Thursday's close. The Nasdaq Composite dropped 1.4% to 27,153.2, the S&P 500 declined 0.6% to 7,750.1, and the Dow Jones Industrial Average slid 0.1% to 51,114.6. Energy and consumer staples led gainers. Among stocks with market capitalization exceeding $200 billion, all of the top 10 names were technology companies, and within those, eight were from semiconductor-related industries, according to data compiled by Finviz. The three worst performers in this mega-cap category were Arm (ARM), Intel (INTC), and Oracle (ORCL), down by at least 6.1% each. Meanwhile, tankers are facing a higher risk of attacks and intimidation as they try to get critical shipments through the Strait of Hormuz after Iran issued new warnings that it would block routes that it has not authorized, sources told Reuters. This comes as tropical storm Isaias continues to strengthen ahead of landfall on the northern Gulf Coast by this weekend, CNN reported. The storm rapidly intensified into the Atlantic season's first hurricane on Wednesday night, the news report added. Chevron (CVX) has begun shut-in procedures for production at four Gulf of America facilities and is evacuating workers as Isaias approaches, the company said. Front-month US West Texas Intermediate crude oil contract advanced 3.8% to $91.67 per barrel, and global benchmark Brent jumped 4.3% to $104.51 per barrel even after President Donald Trump reportedly said Thursday that the US will not attack Iran before the mid-term elections in early November while pointing out "productive discussions" with Tehran. The US borrowing costs at Treasury auctions continued to rise on Thursday. An auction of $22 billion of 30-year bonds hit a high yield of 5.618%, up from 5.308% in the previous auction. The bid-to-cover ratio, which measures demand, declined to 2.54 from 2.61 in the previous auction. On Wednesday, an auction of 10-year bonds also saw the high yield surge in comparison with the previous sale in September. Treasury yields were mixed in the final leg of trading on Thursday, with the two-year down 1.3 basis points to 4.75%. The 10-year rate dropped five basis points to 5.23%, and the 30-year yield slumped six basis points to 5.60%. Both the 10- and 30-year yields traded higher earlier in the session, close to their highest levels since 2002.