• by Mark Walsh  @markfwal, February 1, 2011

In the heated battle among smartphone platforms, it's a virtual three-way tie for U.S. market share among the big three: Apple's iOS, Research in Motion's BlackBerry OS and Android. With Android surging, BlackBerry dropping and Apple holding steady, the trio is knotted with about 28% share each as of December, according to new data from Nielsen.

Those figures are for all smartphone owners. But looking just at people who bought devices in the last six months highlights Android's momentum -- the Google mobile operating system accounts for 43% of recent purchases, compared to 26% for Apple and 20% for BlackBerry.

The Nielsen findings come a day after research firm Canalys reported Android had overtaken long-reigning market leader Nokia's Symbian as the top smartphone platform globally in the fourth quarter. Manufacturers sold 32.9 million Android-powered phones in 4Q, up sevenfold from a year ago, compared to Symbian sales of 31 million.

In the U.S., nearly one-third (31%) of all mobile users owned smartphones at the end of 2010, according to Nielsen. But its latest report spotlights how high-end phones are proving especially popular among ethnic and racial groups. In that vein, 45% of both Hispanics and Asian/Pacific Islanders use smartphones, as do one-third of African-Americans. That contrasts with only 27% of white mobile users.

Similarly, 42% of whites who bought a mobile phone in the past six months chose a smartphone, compared to 60% of Asians/Pacific Islanders, 56% of Hispanics, and 44% of African-Americans.

The iPhone is clearly the device of choice among Asian/Pacific Islanders, with a 36% share. The Apple device is also the top smartphone among Hispanics and whites, with a 29% share of each group, just ahead of BlackBerry, at 27% for both. Nearly one-third (31%) of African-Americans own a BlackBerry, with Android and "other" smartphone platforms close behind at 27% each.

Nielsen has previously predicted smartphone penetration in the U.S. will surpass 50% among mobile users by the end of 2011. But even with high growth, it would take a big jump to get there from 31% at the end of 2010. That compares to about 20% penetration a year ago.