Android held on to its position as the most widely used smartphone OS in the United States over the past three months, but actually decreased its share by 0.2 percentage points between August and October according to new data from market research firm Nielsen. Specifically, Google's mobile platform went from owning 43% of the U.S. smartphone market between July and September to 42.8% in the latest period.

HTC leads all Android manufacturers with 15% market share, followed by Samsung Electronics at 10.4% percent and Motorola Mobility at 10.4%. Apple's iOS grew marginally from 28% to 28.3%, taking the second spot for mobile platforms but easily outpacing any single Android maker in terms of devices sold in the U.S.

Research in Motion took a knock of 1.2 percentage points but its BlackBerry platform is still holding to the third place slot with 17.8 percent market share. Meanwhile, Microsoft's Windows Phone 7 and Windows Mobile operating systems claim a combined 6.1%, with HTC as their top partner.

Nielsen also noted that 44% of all mobile subscribers in the U.S. now own smartphones, and 56% of subscribers who purchased a cell phone in the past three months chose a smartphone. The research firm based its findings on surveys of 22,200 U.S. mobile subscribers.

In a separate report, research firm Strategy Analytics recently said Samsung overtook Apple as the world's top smartphone maker in the July-September quarter, shipping 27.8 million smartphones and accounting for 23.8% of the global smartphone market to Apple's 14.6%. This includes all platforms Samsung works with -- Android, Windows Phone and its own Bada. It should be noted, however, that Samsung doesn't provide sales numbers so it's hard to say how many of those 'shipped' phones were actually sold to consumers.