Payment processor The Members Group has enrolled 25 percent of its issuer clients in Apple Pay, and expects to have 50 percent enrolled by year-end, the company said in news release.

Apple Pay adoption grew at a rate of 21 percent from March to April 2015. Of all FIs now live on the service, nearly 66 percent are credit unions. TMG clients account for roughly 10 percent of all FIs enrolled, the release said.

"Apple Pay has been a good test of the credit union movement's appetite for digital wallet solutions," said Brian Day, TMG director of digital strategy. "Early-adopter clients have been ecstatic about rolling out Apple Pay and report similar enthusiasm for upcoming solutions like Samsung Pay and others."

TMG said that clients have access to a streamlined Apple Pay and tokenization enrollment process, similar to the one TMG built for its clients' migration to chip cards supporting the EMV standard.

The company works with First Data to ensure processing readiness for the client, and also facilitates functions throughout the project, such as coordination of contracts and paperwork, card artwork, meta data, testing, reporting, training, and call center readiness, the release said.