"The average net interest margin in the banking industry is about 2.5 percent," said Guo, "It is expected to drop below 2 percent in the long run as interest-rate reform proceeds."

Interbank deposits were down 307.6 billion yuan from June 30, a decline of 41 percent.

Newly issued wealth management products were taken into the balance sheet, partly offsetting the decrease in interbank deposits.

New loans in the third quarter expanded 3.5 percent from the second quarter.

The proportion of high-yielding loans increased to 54.5 percent from 53 percent in the second quarter.

However, as loan and deposit interest rates are still being readjusted, the rate of return on interest-bearing assets hasn't increased remarkably, according to Pingan Securities.

The other four largest banks - Bank of China Ltd, Agricultural Bank of China Ltd, Industrial and Commercial Bank of China Ltd and Bank of Communications Co Ltd - are scheduled to release their third-quarter statements within this week.

China Galaxy Securities Co Ltd has estimated that the average net-profit growth rate for the top five banks will be 11.4 percent.