Samsung and Apple Dominate the Phone Market

Apple and Samsung Electronics tightened their stranglehold over the US market.

Smartphones from the top two manufacturers made up 68 percent of the US market, according to a recent study from NPD Group. Apple's iPhone franchise made the larger gain, rising to 42 percent in the fourth quarter, or seven percentage points higher than the year-earlier period.

Samsung's share rose to 26 percent in the fourth quarter from 22 percent a year ago.

The big two saw their shares gain even as many of their competitors slid back in the fourth quarter. BlackBerry, unsurprisingly, was the biggest loser, with its share down by nearly two thirds, according to NPD. Motorola and HTC were two other losers, with LG the only other top handset manufacturer to see some year-over-year gains.

The share shift comes as smartphone penetration has increased to 60 percent from 52 percent in the year-earlier period, NPD said. In addition, data usage has grown to 6.6GB per month from 5.5GB per month a year ago.