Apple and Google both gained smartphone share in the U.S. last month according to new data from Nielsen. The research firm on Thursday released a brief detail of the U.S. smartphone market in May following a survey of mobile consumers. Android represented 38% of the smartphone market in May, up two points from 36% in 3-month period ending in April. Apple’s iOS platform gained a single percentage point over the same period to climb to 27%, and RIM’s BlackBerry platform slid two points to 21%. Microsoft’s Windows Mobile and Windows Phone platforms were flat at 9% and 1% respectively, and Palm OS, webOS and Symbian were flat as well. Interestingly, 55% of U.S. consumers who purchased a cell phone in the past three months report buying a smartphone over a feature phone, up from 34% in the same period last year. This is the first time the company determined that smartphones beat out feature phones among recent cell phone buyers. Nielsen also found that Android’s share of recent smartphone acquirers was flat over the past three months while Apple’s iOS was the only smartphone OS to gain share among this group, jumping to 17% from 10% in the prior three-month period. A chart depicting smartphone OS share among recent smartphone acquirers follows below.