Fidelity Investments, one of the world's largest financial services firms, has told its non-U.S. clients that they can't buy or sell mutual funds in their brokerage accounts after July.

A Fidelity spokesman said the policy change relates to “today’s continually evolving global regulatory environment,” but didn't elaborate, according to MarketWatch .

The ban will only apply to about 60,000 overseas accounts, or just under 0.3 percent of the 20 million total accounts at Boston-based Fidelity.

Existing overseas customers with automatic deposits to investment accounts that are being invested in mutual funds will have those funds invested in alternate assets like money market funds.