SEOUL-- South Korean banks saw their third-quarter earnings jump nearly 24 percent from a year earlier due largely to sharply increased interest income, data showed Tuesday.

Their combined net profit stood at 4.6 trillion won (US$3.9 billion) in the July-September period, up 1.1 trillion won from a year earlier, according to the preliminary data from the Financial Supervisory Service (FSS).

In the first nine months of the year, their net income totaled 15.5 trillion won, up 50.5 percent from the same period a year earlier.

The financial watchdog said local banks' third-quarter bottom line soared as their interest income swelled amid rising market rates.

Local banks' interest income came to 11.6 trillion won in the three-month period, up 1.3 trillion won from a year earlier.

Their non-interest income amounted to 1.2 trillion won, down 600 billion won from a year earlier.

The average net interest margin (NIM) of the banks, a key barometer of profitability, had stood at 1.44 percent as of end-September, up 0.44 percentage point from a year earlier.

Their return on assets gained 0.09 percentage point to 0.56 percent in the third quarter, with their return on equity rising 1.07 percentage points to 7.36 percent.

Source: Yonhap News Agency