AI stock selloff may signal market's strongest stretch, history shows

AI stocks lost about $5 trillion in market value since Oct. 6, with Nvidia and Alphabet each shedding roughly $835 billion, while the broader market gained $1.3 trillion. Nine of 11 S&P 500 sectors rose about 1% or more this week, a first since 1999. Stock Trader's Almanac editor Jeff Hirsch calls the sell-off "Octoberphobia" and is buying, citing historical gains from midterm-year Octobers through the following June, with the S&P 500 rising 19 of 19 times since 1950. The iShares Semiconductor ETF fell 17% in October but closed Friday above its July low, suggesting a possible bear trap. Bulls need to reclaim $524, while losing that low could target $370, about 21% below Friday's close.