Jack Henry & Associates Inc. said it has agreed to buy iPay Technologies for $300 million from private-equity firms Spectrum Equity Investors and Bain Capital.

Jack Henry, which processes ATM and debit card transactions and other financial activity, has seen earnings growth accelerate in recent quarters. Global economic improvement has helped the sector but concerns such as bank failures and belt-tightening by financial institutions remain.

Nine-year-old IPay helps its financial institutions provide services such as person-to-person payments, interbank account transfers and electronic bill presentment to retail and small-business customers. It's the largest independent electronic-bill-pay provider in the U.S., Jack Henry said.

The deal is expected to close next month.

Shares in Jack Henry were closed at $25.51 Thursday and were inactive premarket. The stock is up 45% the past year.