Samsung maintained its position at the top of the U.S. smartphone market between March and May.

New data from market research company comScore shows that Samsung products accounted for more than a quarter of all U.S. smartphone sales in the three-month period. LG held 19 percent, ceding some of its market share since the three months ending in February.

Apple, on the other hand, showed the strongest growth, grabbing a 15 percent share of the market, up 1.5 percent. Apple's iOS now runs on nearly a third of all smartphones in the U.S., but the company's share of the operating-system pie grew at more than twice the pace of Google's.