Researcher: Samsung overtook iPhone as best-seller

• Report compares Galaxy to iPhone 4S
• Position likely to be short-lived as iPhone 5 sales kick in
• Galaxy S III launched in May

BOSTON (AP) — A research firm says that Samsung's Galaxy S III overtook Apple's iPhone 4S as the world's best-selling smartphone for the first time in the third quarter.

Boston-based Strategy Analytics said Thursday that the S III shipped 18 million units in the third quarter of this year. Apple's iPhone 4S, meanwhile, shipped 16.2 million units, as many people likely held off to buy its successor. Apple launched the iPhone 5 on Sept. 21.

Strategy Analytics' executive director, Neil Mawston, says the Galaxy's top position is likely to be short-lived. The iPhone 5 sold an estimated 6 million units in the third quarter, which ended on Sept. 30.

Apple shares continued their recent decline in morning trading, falling $8.62, less than 2 percent, to $549.38. The stock was over $700 two months ago.

Samsung on Monday said it has sold more than 30 million of the flagship Galaxy S III smartphones in about five months, making it one of the fastest selling smartphones in the world.

Samsung Electronics, the world's biggest mobile phone maker, launched the smartphone at the end of May, months before competitors began shipping the latest versions of their top phones.