Google's Android OS was the only mobile platform experiencing significant growth in the US during the three months ending in January, carving out over four percentage points of market share, ComScore said.
While Android remained in fourth place, its share of the market increased to 7.1% from 2.8%, the research firm calculated.
Google's gain was third-placed Microsoft's loss. Microsoft's share of the smartphone market shrank four percentage points to 15.7%.
Meanwhile iPhone sales stalled, with Apple's share increasing just 0.3 percentage points to 24.8%. But Apple maintained the second spot behind RIM, whose market share grew from 41.3% to 43%.
Palm's share continued to fall, with the company losing 2.1 percentage points but holding onto fifth place with a 5.7% share.