International Business Machines Corp. bought Expertus Technologies Inc., a Canadian financial-technology firm that helps process more than $50 billion in transactions a day, to bolster its electronic-payments capabilities.

Closely held Expertus has been added to the IBM Global Business Services unit, the Armonk, New York-based buyer said in a statement. Financial terms of the deal weren’t disclosed.

Banks worldwide are investing around $100 billion to modernize their payment systems and keep up with innovative rivals including PayPal Holdings Inc. and Square Inc., said Shanker Ramamurthy, global managing partner for banking in IBM Services. Buying Expertus will allow IBM to help banking clients meet those challenges while controlling expenses and complying with regulatory requirements, he said.

“Payments represent a very profitable part of their franchise, and they want to continue to ensure they hold onto and not see erosion in that business in this new digital-banking environment,” Ramamurthy said in an interview.

More than 1,000 banks, credit unions, regulatory agencies and corporations use Expertus’s payment platform. The Montreal-based firm is also one of the largest North American services bureaus of the Society for Worldwide Interbank Financial Transactions, or SWIFT, a network banks use to manage money transfers and treasury transactions.