CardSystems, a provider of electronic payment processing services for financial institutions, has raised $9.3 million in a new round of financing.

Camden Partners, a private equity firm based in Baltimore, led the investment. Other existing investors also contributed, CardSystems said. Camden Partners led a $23 million investment in the company in 2003.

The company said the funds would be used to expand its processing and merchant acquiring services.

“We are extremely pleased to have an investment of this size in CardSystems; it is a clear demonstration of confidence in the company’s technology platform, client base and new management team,” said John Perry, president and chief executive officer of CardSystems. “This funding is an important step in positioning CardSystems for future growth.”

In July, the company named Cabot Rohrer as senior vice resident for operations and William Reeves as vice president of marketing.

In August, Paul Oswald was named senior vice president for sales.

CardSystems applications are in use at more than 11,000 merchants.