Impact of the iPhone 4S launch was ‘enormous,’ says Nielsen by Philip Elmer-DeWitt @FortuneMagazine January 18, 2012, 12:33 PM EST E-mail Tweet Facebook Google Plus Linkedin Share icons Between October and Christmas, Apple’s U.S. sales nearly caught up to Android’s Click to enlarge. Source: Nielsen Three findings stand out in Nielsen’s December survey of the U.S. mobile phone market, released Wednesday: Among recent smartphone buyers, 44.5% of those surveyed in December bought an Apple AAPL iPhone, up from 25.1% in October 57% of new iPhone buyers said they chose the iPhone 4S over the less expensive iPhone 4 or iPhone 3GS Android’s lead among recent buyers nearly evaporated in the space of two months; in the December survey, 46.9% said they purchased a phone running Google’s GOOG operating system, down from 61.6% before the iPhone 4S’ Oct. 14 launch. Among all smartphone owners, Android still leads iPhone 43.6% to 30%. Note that Nielsen has mixed and matched its time frames and offered no demographic color, not even the number of households surveyed. But the fever chart (above) it released Wednesday matches — more or less — the right-hand side of the one (below) that the NPD Group sent out nine days earlier. See NPD: iPhone surged, Android slipped in Oct. and Nov. Below the fold: Two Nielsen bar charts from the same report.