Coupang's users and payment amount, which triggered a massive personal data leak in Nov. last year, climbed to levels exceeding those before the incident. During the same period, homegrown e-commerce firms such as Gmarket, 11Street, and SSG.com saw both users and payment amounts decline.
According to IGAworks Mobile Index on the 9th, Coupang's estimated credit and debit card payment amount in Aug. was 4.9301 trillion won, 6.8 times the combined amount of Gmarket (247.7 billion won), 11Street (241.4 billion won), and SSG.com (238.3 billion won). The gap, which was 4.6 times in Jan. this year, has widened. Coupang's payment amount last month rose 11.9% from Jan., while Gmarket fell 44.0% over the same period, and 11Street and SSG.com decreased 5.7% and 7.5%, respectively. Coupang's payment amount in Jul. was 5.0942 trillion won, surpassing 5 trillion won for the first time on a monthly tally basis.
The contrast is also clear in user metrics. Coupang app's monthly active users (MAU) in Aug. reached a record-high 35.95 million. That was up 2.31 million from the Feb. trough (33.64 million) and 1.57 million more than in Oct. last year (34.38 million), before the information leak incident. In contrast, 11Street's Aug. MAU was 6.88 million, down 1.07 million (13.5%) from the previous month (7.95 million), dropping below the 7 million mark. Gmarket also fell to 6.16 million, down 9.9% from Jan. (6.83 million). SSG.com stood at 2.85 million, about one-thirteenth the level of Coupang.
Coupang's rapid rebound is attributed to the so-called "Coupang ecosystem." The 7,890 won-per-month "Wow membership" bundles free shipping and free returns with free viewing of Coupang Play and delivery fee discounts on Coupang Eats. In particular, Coupang Play, strong in sports broadcasting, aired throughout Aug. the "Team K League" vs. Manchester City match under the "2026 Coupang Play Series," the Leagues Cup featuring Son Heung-min, and the recently opened English Premier League (EPL) 2026-27 season, lifting users by 16% in a month. Inflows continued even after it raised the sports pass fee for new subscribers by up to 25% in Jun.
The first pillar of Coupang's edge is direct purchasing. Coupang buys products in advance, stocks them at logistics centers nationwide, and ships them through its own delivery network. Because it controls both inventory and delivery directly, it can offer dawn and same-day delivery and 30-day free returns. By contrast, Gmarket and 11Street mostly rely on a structure in which sellers hand over parcels directly to couriers, so delivery times and return procedures vary by seller even for the same product. From a consumer's perspective, the key dividing line is whether "when it arrives, and what happens if you don't like it" is fixed.
Coupang is also absorbing into Coupang delivery even items sold by open-market sellers. If a seller stocks products at a Coupang logistics center, Coupang handles storage, delivery, returns, and customer service under "Rocket Growth." These products carry a "Seller Rocket" badge, are prioritized in search results, and are delivered on Sundays and holidays. Although they are open-market items, the consumer experience is effectively the same as Rocket Delivery. For sellers, outsourcing logistics and customer service allows them to focus on sourcing and marketing, increasing the incentive to join Coupang's logistics network as they scale.
Rivals are not sitting idle. However, fully replicating a nationwide Rocket Delivery network requires massive logistics investment, so instead of a head-on clash, they have shifted to targeting areas that are relatively harder for Coupang to cover. SSG.com, for example, is expanding "Baro-Quick," which uses E-MART stores as delivery hubs to deliver products in around an hour.
Still, such investments have yet to show up in the metrics. An e-commerce industry official said, "Sellers flock to platforms with many users, and as product assortment and lowest prices pile up at Coupang, the 'penning-in effect' may be pushing consumers toward Coupang." Another official said, "After Coupang's personal data leak, each company waged an all-out promotion war, but customers tied to Wow are found to be reluctant to move."
The exception is Naver. MAU for Naver Plus Store rose nearly 30%, from 6.97 million in Jan. to 9.04 million in Aug. The user gap with Coupang narrowed to about fourfold. It is effectively the only homegrown platform catching up with Coupang. However, Naver Plus Store's payment data is not included in the aggregation target, making payment amount comparisons impossible. Mobile Index said the payment amounts this time are figures estimated by an artificial intelligence (AI) algorithm based on credit and debit card data and may differ from actual sales.