Apple's capital return program will get much larger, according to one Wall Street firm.

UBS reiterated its buy rating on Apple shares, saying the recently passed tax reform law will free up new funds for the company's shareholder return program.

"Apple clearly is a beneficiary of overseas cash repatriation," analyst Steven Milunovich wrote in a note to clients Monday. "Repatriation of ~$250bn of offshore cash should increase the rate of Apple's share buybacks since the company believes the stock remains attractive in that its services business is undervalued."