South Korean credit card companies have underperformed in the first quarter of this year, largely due to a decrease in income from commissions charged on member stores, data showed Wednesday.

Net income of Shinhan Card Co., the No. 1 credit card firm by market share, dipped 13.9 percent to 160.6 billion won ($145.4 million) in the January-March period, compared with 186.6 billion the previous year, according to the card company and regulatory filings.

Samsung Card Co. saw its first-quarter earnings slip 7 percent to 66.5 billion won in the same period, the data showed.

KB Kookmin Card Co. logged a net profit of 95.6 billion won in the first three months of this year, up 34.3 percent from a year ago, but that was largely due to one-off gains. Excluding the one-off profit, the firm’s net profit sank 8 percent, the data showed.

Their weaker bottom line came as the regulator imposed a revised credit finance rule in which credit card companies are required to lower the commission rates they charge smaller stores, and hike the rate for larger firms. (Yonhap News)