According to recent estimates from market researcher Strategy Analytics, Apple (NASDAQ:AAPL) has become the No. 1 smartphone vendor in the United States for the first time ever. The company shipped 17.7 million iPhones domestically in the fourth quarter for a record 34% market share.

Rival Samsung closed out the quarter as a close second with 16.8 million units shipped in the U.S., representing a 32.3% market share. The No. 3 vendor was LG with 4.7 million units and a 9% slice of the market. Strategy Analytics said that the overall domestic smartphone market shrank by 11% to 166.9 million units throughout all of 2012, due to weakness in the first three quarters from economic uncertainties and tighter upgrade policies at major carriers.

The researcher added that Apple's success was driven by its broad ecosystem, hefty carrier subsidies, and extensive marketing.