Space Defense Newcomer Plummets 17% in a Day, $750 Million Market Cap Vanishes

Shares of space-defense small-satellite manufacturer York Space Systems Inc. (YSS) plunged more than 17% on the New York Stock Exchange. On June 11, the stock closed at $27.90, down 17.26% for the day on trading volume exceeding 1.68 million shares. Its market capitalization fell to about $3.6 billion (roughly 5.1 trillion won), erasing approximately $533 million (around 750 billion won) in a single session.

In its first-quarter report, York Space Systems posted revenue that was 9.5% higher year-over-year but remained unprofitable due to IPO-related expenses. The company also disclosed a transaction to acquire solar-cell maker Solestial for about $67 million (approximately 94 billion won) in a combination of stock and cash, stoking concerns over potential equity dilution. A recent research note recommending a short position—citing ongoing losses and a high valuation—appears to have cooled short-term investor sentiment further.

Founded in 2015 and based in Colorado, York Space Systems manufactures and operates small satellites, supplying mass-produced satellite platforms and space-infrastructure solutions to the U.S. Department of Defense, government agencies, and commercial clients. The company went public on the New York Stock Exchange in January 2026 at $34 per share, raising about $629 million (roughly 880 billion won) and achieving an initial market valuation of approximately $4.75 billion.