The chips that powered the artificial-intelligence rally are now leading its retreat.

The PHLX Semiconductor Index, the main benchmark for U.S.-listed chipmakers, which is closely tracked by the Invesco PHLX Semiconductor ETF (NYSE: SOXQ), has fallen for seven straight sessions.

That has happened only 15 times since 1994.

The index is down nearly 14% from its Oct. 6 close.

According to market data, these are the worst-performing stocks over the past seven sessions among companies with at least a $50 billion market cap.

Two forces are behind the sell-off.

China's ChangXin Memory Technologies reported progress on a denser memory chip design, raising fears of future oversupply.

Meanwhile, U.S. producer prices rose 6.3% from a year earlier in September, the fastest pace since December 2022. That keeps a Federal Reserve rate hike on the table.

Higher rates make it more expensive to borrow and build AI data centers. As a result, investors are dumping the companies that sell memory, storage and chipmaking tools to those data centers.

The Roundhill Memory ETF (NYSE: DRAM) has lost 21% since its Oct. 5 close.