KB Financial Group Inc., Korea's biggest retail bank, said Thursday it posted a 20.1 percent on-year jump in net profit in the first half on decreased burden in labor costs and loan-loss provisions.

Net profit for the six months ended June 30 climbed to 1.125 trillion won ($990 million), up 188.7 billion won from a year earlier, KB Financial said in a regulatory filing.

The first-half net result beat market expectations.

KB Financial attributed the jump in first half earnings to decreased financial burden in terms of wages following last year's voluntary retirement program.

KB Financial also said it had less burden from loan-loss provisions in the first half as it preemptively put aside ample provisions in past years.

Kookmin Bank, the group's flagship unit and the largest local lender, posted a net profit of 743.2 billion won in the first quarter, up 1.8 percent from a year earlier, KB Financial said.

The bank's net interest margin -- which measures profitability from lending -- stood at 1.58 percent in the first quarter, the group said. The net interest margin indicates the difference between interest paid out on deposits and interest gained from lending.

Shares of KB Financial ended up 0.73 percent to 34,350 won on the Seoul bourse. (Yonhap)