PHLX Semiconductor Sector Index drops 7.8 percent on post-election session

Semiconductor names led the selloff with Nvidia falling 9.4 percent, AMD 8.7 percent and Intel 7.1 percent. Volume on the SOX reached 142 million shares against a 20-day average of 68 million. The move followed 10-year Treasury yields rising 17 basis points and the dollar index gaining 1.1 percent intraday.

Historical records from the Dow Jones back to 1896 show only two comparable post-midterm sessions with larger percentage declines; both occurred under rising real-rate regimes above 2 percent. Current SOX forward P/E compressed from 22.4x to 20.8x in one session, the steepest one-day derating since March 2020.

The decline exposed concentration risk: the five largest SOX constituents accounted for 58 percent of index weight yet contributed 71 percent of the point loss. Supply-chain data from Taiwan Semiconductor showed October wafer starts flat month-over-month, contradicting earlier analyst models that assumed 8 percent sequential growth.

Operational impact appears in deferred equipment orders. ASML reported two EUV system pushouts from a single customer in the same week. Forward guidance revisions are expected from at least three additional SOX members before month-end.