Interviews with people involved revealed that the Japan corporation that operates Costco, a large membership-based supermarket, had improperly sold duty-free goods to foreign customers and had been charged an additional tax of approximately 15.<> billion yen after the Tokyo Regional Taxation Bureau pointed out a miscalculation of the amount of consumption tax.

The additional tax was levied on Costco Wholesale Japan, a Japan subsidiary of Costco, a large membership-based supermarket headquartered in the United States, located in Kisarazu City, Chiba Prefecture.

According to the officials, inappropriate measures were confirmed at some Costco stores in Japan, such as selling products duty-free to foreign customers suspected of reselling, such as purchasing a large number of home appliances at once.

In addition, there was a mistake in the calculation of the tax amount, so the Tokyo Regional Taxation Bureau pointed out to "Costco Wholesale Japan" that about 8.5 billion yen of consumption tax was not declared in the five years to August last year, and about 14.15 billion yen was additionally levied, including the underdeclaration additional tax.

According to Costco's website, Costco has 1.2790 million members worldwide and 33 stores in Japan.