Nielsen detects a preferential shift that reflects Android's ascension, which has happened rapidly in the last six months.
Google's Android operating system rose to 37 percent U.S. market share compared with 27 percent for Apple's iPhone through March, according to the latest Nielsen data.
That's up 8 percent from Nielsen's March 3 accounting for January, when the researcher said Android notched 29 percent, breaking a statistical tie with Apple's iOS and Research In Motion's BlackBerry platforms.
Nielsen also detected a preferential shift that reflects Android's ascension, which has happened rapidly in the last six months.
When Nielsen surveyed U.S. mobile consumers from July to September 2010, one-third of the respondents said they wanted an iPhone, compared with 26 percent who said a handset running Android was on their shopping list.
However, when Nielsen conducted the same survey from January through March 2011, 31 percent of consumers who plan to acquire a new smartphone said they were looking to buy an Android device. No slouch itself, the iPhone dipped to 30 percent.
When Nielsen followed up its calculations, 50 percent of those surveyed in March 2011 who said they had purchased a smartphone in the past six months said they had picked an Android device. Samsung's Galaxy S devices, the Motorola Atrix 4G, and the HTC ThunderBolt likely helped account for those sales.
Some 25 percent of recent acquirers said they bought an iPhone, no doubt buoyed by the launch of the iPhone 4 on Verizon Wireless, while 15 percent said they had picked a BlackBerry phone.
Nielsen now rates BlackBerry No. 3 behind iOS with 22 percent of the U.S. smartphone market.
Nielsen isn't the only vendor to chart Android's rise. ComScore said earlier this month that Android now commands 33 percent U.S. smartphone share, compared with 25 percent for the iPhone.
However, comScore also noted last week that the prevalence of Apple iOS devices outpaced Android gadgets by 59 percent.
Specifically, the researcher said iPhones, iPads and iPod Touches combined to reach 37.9 million users, compared with 23.8 million combined Android smartphone and users of the Samsung Galaxy Tab, Motorola Xoom and other Android tablets.