Strong Performance Yet… $5 Billion Vanished in a Day for Cloud Security Stocks

Shares of Zscaler Inc. (NASDAQ: ZS), a U.S. cloud security provider, plunged 17.03% in Nasdaq trading on the 26th, closing at $151.77 (approximately KRW 210,000). The company’s market capitalization fell to about $24.4 billion (roughly KRW 34 trillion), erasing an estimated $3.6 billion (around KRW 5 trillion) in market value intraday. Trading volume reached approximately 6.41 million shares as heavy selling swept the stock.

After the market closed that day, Zscaler reported third-quarter results for its fiscal year 2026, with both earnings per share and revenue surpassing analysts’ forecasts. The company also issued full-year guidance. Nonetheless, shares fell despite the positive earnings surprise, as investors remained wary of future growth prospects and valuation levels. Still, given the expanding demand for AI and zero-trust security solutions, expectations for the company’s mid- to long-term growth remain robust.

Zscaler is a leading cybersecurity vendor offering Zero Trust Exchange, a cloud-based platform that brokers access to the internet, SaaS, and on-premises applications under a zero-trust model. By replacing traditional VPNs and firewall appliances, Zscaler serves global enterprises and public-sector institutions and is widely regarded as a key beneficiary of the ongoing shift to cloud computing and AI.