South Korean online lender K-Bank said Tuesday it posted the strongest performance for any first half on increased interest revenue.

K-Bank's first-half net income stood at 45.7 billion won ($34.9 million), far beyond the 22.5 billion-won annual net profit of last year and marking the highest first-half earnings since its launch in 2017, the bank's data showed.

The online lender attributed the record earnings to more account openings, expansion in loan portfolios and diversified sources of profit.

First-half interest revenue soared to a record 172.1 billion won, thanks to the rising interest rates.

The internet-only bank reported a steep growth in mortgage loans, in particular.

As of end-June, the portion of its collateral-based loan plans against total lending stood at 21.1 percent, sharply up from 13.7 percent from a year ago.

But its second-quarter net profit fell to 21.3 billion won from 24.5 billion won a year earlier, the bank said in a statement.

The fall in quarterly net profit was the result of increased provisions for bad debt.

In July, the Bank of Korea raised its key interest rate by 0.5 percentage point to 2.25 percent, the steepest and sixth increase in borrowing costs since August last year.

K-Bank, South Korea's first internet-only bank that started operation in 2017, is controlled by a consortium of telecom giant KT Corp., Woori Bank and 19 other firms.

The number of K-Bank customers stood at 7.83 million as of end-June, up 0.66 million from six months ago. (Yonhap)