South Korea's internet-only lender, K bank, witnessed a significant improvement in its earnings as it gears up for its market debut this year.

The bank announced Monday that its net profit in the first quarter surged nearly fivefold to 50.7 billion won ($37 million), from 10.4 billion won in the same period last year, reaching a new quarterly high.

The bank stated the record performance results from a balanced growth in both deposit and loan balances, which increased by 25.7 percent and 6.6 percent, respectively, from the previous period, totaling 23.97 trillion won and 14.76 trillion won, respectively.

Notably, its loan portfolio saw significant growth this quarter, with the outstanding balance of apartment mortgage loans increasing by 1 trillion won and lease loans by around 300 billion won.

The influx of new customers continued, with approximately 800,000 joining in the first quarter, bringing the total to 10.33 million.

With the expansion of its customer base, K bank's interest income surged by 32 percent on year to reach 136 billion won. During the same period, non-interest income nearly doubled from 8.1 billion won to 15.7 billion won.

The default rate improved slightly from 0.96 percent to 0.95 percent, while the loan provision volume decreased by 19.7 percent on year to 48.4 billion won, contributing to profit enhancement.

The bank's net interest margin, a key profitability indicator, improved to 2.4 percent, while the cost-to-income ratio dropped to 29 percent, showcasing strong cost efficiency among local banks.

Launched in 2017, K bank aims for an initial public offering on the local stock market within this year, with a market valuation estimated at around 4 trillion won. Lead underwriters were selected in February, and the bank plans to apply for a preliminary listing review with the Korea Exchange in the first half of this year.