The bank said increased growth in its loan book, depositors, and a more favorable macro-economic outlook in the region helped spur pretax profit growth to 13 billion shillings in the period between January and September.

The bank released its results after the Nairobi Securities Exchange had closed trading, but equity analysts expected the company's stock to jump when trade resumes on Friday.

"We had expected they would be good, but this is spectacular," said Johnson Nderi, an analyst at Suntra Investment Bank.

"We expect a price jump when the market opens tomorrow."

The bank's shares closed at 29.50 shillings.

KCB's stock is among the top performers on the Nairobi bourse, gaining 75.1 percent so far this year and outpacing Nairobi's benchmark index that is up 27.8 percent.

The bank, which also has operations in Tanzania, Rwanda, Uganda, South Sudan and recently in Burundi, said net interest income for the period climbed 31 percent to 21.7 billion shillings, the bank said.