SEOUL, May 27 — Starbucks Korea’s sales have taken a sharp hit after backlash over a promotional campaign accused of mocking one of South Korea’s darkest chapters in modern history, according to new data reported by the Korea JoongAng Daily.

Figures released today showed the coffee chain’s weekly payment volume plunged by more than 8 billion won (RM22 million) in the immediate aftermath of the controversy surrounding its “Tank Day” tumbler promotion.

Data from Mobile Index, operated by AI analytics firm IGAWorks, showed Starbucks Korea recorded 23.69 billion won in payment volume between May 18 and Sunday, down 26.3 per cent from the 32.16 billion won logged the previous week.

Compared with the week before that, spending was also down by roughly a quarter, underlining the speed at which consumer sentiment appeared to sour.

The controversy erupted after Starbucks Korea used phrases such as “Desk bang! Tank Day” during a discount campaign held on May 18 — the anniversary of the 1980 Gwangju Democratisation Movement, a defining pro-democracy uprising brutally suppressed by military forces.

Critics accused the campaign of trivialising the tragedy by invoking imagery associated with tanks and state violence.

The fallout appears to have extended beyond store purchases.

New installations of the Starbucks Korea app fell 23.6 per cent during the same period, dropping from 48,441 to 36,994 downloads week-on-week. The app also slipped from second to fifth place among food and beverage brand apps for new installs.

Still, weekly app users rose by 4.7 per cent to just over four million users, with observers suggesting existing customers may have logged in more frequently to check coupons, rewards points or prepaid balances.

Shinsegae Group chairman Chung Yong-jin issued a rare public apology this week, admitting the company had suffered “a significant decline in sales”.

An internal investigation later concluded there was no clear evidence the campaign had deliberately mocked the Gwangju movement, though the damage to public perception may already have been done.