Aftermath of Data Breach: Coupang's Stock Plummets 5% in One Day

Coupang (COUPANG INC: CPNG) shares closed at $20.93 on the New York Stock Exchange on the 13th, down 5.48%. Its market capitalization fell by about $1.8 billion in a single day to roughly $34.9 billion, wiping out around KRW 2.4 trillion. Analysts attribute the drop to investor concerns over a large-scale customer data breach and related litigation risks.

U.S. class-action lawsuits against Coupang are multiplying. As of January 8, several law firms are representing Coupang investors in securities-law violation claims and are urging shareholders to join. Some litigation deadlines extend as far out as February 17, 2026.

In December 2025, Coupang disclosed a major data breach involving attempted access to approximately 34 million accounts. During the ensuing investigation, the company confirmed that the incident stemmed from an internal breach involving a former employee. The Personal Information Protection Commission is currently probing the matter, and the market is speculating on potential fines of up to around $700 million (about KRW 900 billion).

Founded in 2010 by Chairman Bom Suk Kim, Coupang is South Korea’s leading e-commerce company. Since its listing on the New York Stock Exchange in 2021, it has expanded its share of the domestic online retail market through its “Rocket Delivery” logistics network.