Thanks to strong sales of the iPhone 5 over the last few months, iOS is once again the number one mobile platform in the US. It now handles the operating on 48.1% of smartphones sold in the States during a 12 week period that ended on 28 October, compared to Android and its 46.7% smartphone market share over the same period.

Dominic Sunnebo, global consumer insight director at KWC explained that the last time Cupertino’s mobile platform managed this feat was when the iPhone 4S (review) was released. During that time, the iPhone 4S provided Apple with its highest ever share (49.3%) of the US smartphone market, but the market research firm asserts that Cupertino will likely exceed that share now due to the popularity of the new iPhone.

iPhone 5 and brand loyalty drives Apple’s US smartphone growth

KWC asserts that the majority (62%) of all US iPhone 5 sales is a result of existing iPhone owners upgrading to the newest smartphone from Cupertino. Apple also benefitted from Android users switching over to iOS (13%), and users (6%) of RIM’s (Research In Motion’s) BlackBerry smartphones making the leap to the iPhone.

Sunnebo commented: “Apple has always managed to maintain loyalty levels far above the competition, and this has clearly played a part in driving sales of its new device. An impressive 92% of existing Apple owners in the US said they will choose an iPhone the next time they upgrade.”

“While loyalty is clearly key, it is also important to make sure that new customers are attracted to your brand. With roughly 60% of US iPhone 5 sales coming from existing customers and 40% from new consumers, Apple is achieving this at the moment – a clear sign of the strength of the brand in the US marketplace,” he added.

Android on top in Europe

Although iOS is gaining more traction Stateside, Android is still the platform of choice within Europe. Android accounts for 73.9% of smartphone sales in Germany alone and a whopping 81.7% in Spain. Google’s popular mobile operating system (OS) is also winning over many smartphone buyers in the UK, where the OS holds a 54.2% market stake, up from 46.6% for the same period last year. The UK is, however, one of the key EU markets where iOS is doing well, with a stake of 32.7%, representing a market growth of 5% compared to this time last year.

Sunnebo stated that Germany remains to be a tough market for Apple as its market share decreased by 5.1% over the past year. Samsung’s ultra popular Galaxy S3 (review) provided Android with a significant market boost, as this smartphone alone represented 25% of Germany’s smartphone sales over a 12 week period up until 28 October.

Within Italy, Microsoft’s Windows Phone OS holds a 11.7% share of the smartphone market, which marks the highest market stake across Europe. The popularity of Redmond’s smartphone platform was given a boost in Italy courtesy of strong sales of Nokia’s Lumia 610 (review, 4th best selling smartphone in Italy) and the Lumia 800 (review, 7th best handset smartphone).

In related news, the latest research from market intelligence firm ABI Research recently showed that Apple’s share of the tablet market dropped by nearly 14% during Q3 2012 to its lowest level (55%) since launching the original iPad (review) in 2010.