South Korea's Personal Information Protection Commission said Coupang had leaked personal data of more than 33 million customers and failed to detect the breach within the 72 hours required by law. © ReutersSEOUL (Reuters) -- South Korea will fine e-commerce giant Coupang 625 billion won ($409.30 million) over a massive leak of customer information last year and illegal collection of personal information, in the country's largest corporate penalty for a data breach.The Personal Information Protection Commission said the New York-listed company had leaked personal data of more than 33 million customers and failed to detect the breach within the 72 hours required by law.The fine amounts to 1.4% of Coupang's revenue of 45 trillion won in 2025, according to Reuters' calculation."This accident occurred due to Coupang's lack of safety measures and systems, not sophisticated hacking," Song Kyung-hee, the chairperson of the privacy regulator, told a briefing on Thursday.After the fine was announced, Coupang apologized for having caused concern to the public and its customers.However, the company also said that it regretted "our proactive measures to prevent secondary harm from last year's data leak incident, as well as our explanations based on clear facts, were not sufficiently reflected" in the regulator's decision.Seattle-based Coupang generates most of its revenue in South Korea, offering fast delivery of groceries, food and other goods.