Jazib Zaman

SanDisk ended the first half of 2026 as the best-performing stock in the S&P 500, up 858% — from a $237.38 close on December 31 to $2,273.73 on June 30. Two sessions later, $529 of that share price was gone. Thursday's 14.1% drop — the stock's biggest one-day fall since early February — capped a 23.3% two-session slide and sent SanDisk into the July 4th weekend at $1,745, with US markets shut until Monday, July 6. What changed is the question being asked of the stock.

On June 24, one minute after the closing bell, Micron reported the largest quarter any standalone memory company has ever posted: $41.46 billion in revenue, up 346% in a year, at an 84.9% gross margin. The stock jumped 15.7% the next day to a record close of $1,213.56. Five sessions later, all of it was gone — and then some. Micron ended Thursday at $975.56, seven percent below where it traded before the report came out.

Thursday's selloff priced in an AI memory glut that, on every published construction timeline, does not exist yet. SanDisk closed down 14.1% at $1,745. Teradyne lost 13.6%, KLA 11.5%, Seagate 10.4%, Lam Research 10.2%. The Philadelphia Semiconductor Index fell 5.4% on top of Wednesday's 6.3% — an 11.4% wipeout in two sessions — while the Dow rose 595 points to a record close of 52,900.07. Thursday was not a market panic. It was a targeted unwind of the single most profitable trade of 2026.