Android's market share dropped and Apple iOS' share grew as smartphone unit sales decreased in the U.S during the second quarter, according to market research company Strategy Analytics.
Overall smartphone shipments in the U.S. fell 5 percent year-on-year to reach 23.8 million units.
A volatile economy, maturing penetration of smartphones among contract mobile subscribers and major operators tightening their upgrade policies to enhance profits were among the main causes for the drop in unit sales, Strategy Analytics said.
Google's Android is still the most popular OS by a wide margin. However, an estimated 13.4 million Android-based smartphones were shipped during the second quarter resulting in a 56 percent share of the U.S. market. That compares to 15.3 million units and a 61 percent share during the same period last year, according to Strategy Analytics.
At the same time, Apple's U.S. market share grew from 23 percent in the second quarter last year to 33 percent. Apple's unit sales increased from 5.9 million to 7.9 million smartphones.
"Apple is rumored to be launching a new iPhone in the coming weeks, and that event, if it takes place, is going to heap even more pressure on Android in its home market," said Neil Mawston, executive director at Strategy Analytics.
BlackBerry's smartphone market share in the U.S. has dropped from 10.5 percent to 6.5 percent over the past year.
"Consumers, businesses and operators continue to be frustrated by BlackBerry's limited touchscreen smartphone portfolio and repeated delays to its new BB10 operating system," said Scott Bicheno, senior analyst at Strategy Analytics.
In the second quarter global smartphone shipments reached 146.1 million units and grew 32 percent, which was the smartphone industry's slowest growth rate since the third quarter of 2009, according to Strategy Analytics.