South Korea hit e-commerce giant Coupang with a record $408 million fine Thursday over a leak that allegedly exposed more than 30 million customers' data.
Coupang, the country's largest online retail platform, signaled in a statement that it would challenge the fine in court.
The government's move caps a months-long probe into Coupang, which is incorporated in the United States.
Allegations of a massive data leak first surfaced in November.
It is by far the largest ever penalty for a data leak in South Korea, far exceeding the previous record of a $88 million fine imposed last year on mobile carrier SK Telecom.
"Inadequate basic safeguards, including poor management of authentication signing keys and lax access controls" caused the personal data of around 37.5 million users to be exposed, Seoul’s Personal Information Protection Commission said.
Coupang has maintained that only 3,000 customer records were involved.
In April, South Korean lawmakers sent a joint letter raising concerns over "undue pressure" from U.S. politicians regarding Seoul's investigation into the e-commerce giant.
The letter, co-signed by nearly 100 MPs, followed accusations by U.S. Republicans that the probe into the U.S.-listed company constituted "discriminatory regulatory actions" against American businesses.
The dispute has also reportedly affected high-level security talks between the two allies, according to local media.
Washington is said to have warned it would halt such talks unless the legal protections of Coupang chairman Kim Bom -- an American citizen also known as Kim Bom-suk -- were guaranteed.
