CIBC declined to comment on the financial details of the acquisition.

For the quarter ended July 31, CIBC's Canadian credit card portfolio's average balance was C$10.6 billion, accounting for about 4% of its total domestic personal loan book.

The bank will become the exclusive issuer of Costco Mastercard in Canada, CIBC said, adding that Mastercard will remain the exclusive payments processor for the Costco co-branded credit card portfolio.

CIBC expects the purchase to close in early calendar year 2022, after which it will begin issuing CIBC Costco Mastercard to the converted portfolio and take new applications.

($1 = 1.2594 Canadian dollars)

(Reporting by Sohini Podder in Bengaluru and Nichola Saminather in Toronto)