Samsung has for many months led Android's charge in the US, but according to comScore, March saw its share of the market slip for the first time in almost a year.
That's a trend that's been replicated in the firm's report for April.
Apples and Androids
According to numbers pooled from comScore's MobiLens service, Samsung held 24.5 percent of the market in April down 0.4 percentage points from January.
What's more, the company's nearest competitor LG saw its share pick up across the same period, up 0.1 percentage points to 20.9 percent.
The big news, however, is that Apple has finally overtaken RIM to become the fourth largest mobile OEM in the US, as predicted.
Apple's share rose 1.3 percent in the three month period to finish on an 8.3 percent share of the 234 million mobile subscribers currently in the US market.
It'll be some time before Jobs and co. can move on to snatch third position, though Motorola's share continues to fall back, down 0.9 to 15.6 percent.
Black days for BlackBerry
Naturally, Apple's success as a mobile manufacturer has had an equal impact on the standing of iOS, though comScore claims Android is still leagues ahead of its great rival.
Android now holds more than 36 percent of the market, growing at more than 5 percent every three months.
BlackBerry's fading fortunes, however, means RIM is falling back at a similar rate, while Microsoft also continues to lose share in its home territory with Windows Phone 7.
You can view a summary of comScore's latest findings on the firm's website.
