Semiconductor Equipment Stocks Lose 800 Billion in a Day... Growth Stock Rally Hits a Sudden Brake

On July 1, shares of semiconductor-equipment maker ACM Research Inc. (NASDAQ: ACMR) plunged 7.87%, closing at $116.90 (approximately ₩150,000) on the Nasdaq. The slide wiped out about $540 million in market value (roughly ₩800 billion). As a result, the company’s total market capitalization fell to about $7.5 billion (around ₩10 trillion), and trading volume exceeded 1.4 million shares, reflecting unusually high volatility.

Although ACM Research reported first-quarter 2026 revenue growth of over 30% year-on-year—outperforming market expectations—margin pressure and slowing profit growth came into focus, driving increased share-price volatility after the earnings release. In addition, during the late-June Russell index rebalancing, ACMR was removed from several value indices and reclassified into a growth index. Market watchers say this shift, combined with a pullback in growth-stock positions, triggered profit-taking.

Headquartered in Fremont, California, ACM Research supplies process equipment for semiconductor wafer cleaning and thin-film deposition. Because its principal customers are Chinese foundries and memory manufacturers, the company is heavily exposed to the Chinese market through its Shanghai subsidiary. Key factors influencing ACMR’s share price include its Chinese revenue mix, U.S. export-control risks, and earnings volatility stemming from aggressive growth investments.