LONDON: Sales of Apple's new iPhone 5S and 5C models have performed well, according to Kantar Worldpanel ComTech, but the brand's share of major markets is lower than it was a year ago.

Quarterly OS barometer figures from the research company showed that, in the three months to the end of November 2013, Apple's mobile operating system, iOS, accounted for 69.1% of the market in Japan, 43.1% in the US, 35.0% in Australia and 30.6% in the UK.

The previous year, these shares stood at 53% in the US, 35.5% in Australia and 36.1% in the UK. No data was collected for Japan.

"While there's no doubt that sales of the iPhone 5S and 5C have been strong, resurgent performances from LG, Sony and Nokia have made making year-on-year share gains increasingly challenging for Apple," said Dominic Sunnebo, strategic insight director at Kantar Worldpanel ComTech.

He pointed to the example of Windows Phone, now the third largest OS across Europe with a 10% share, which was more than double its share of a year earlier. But Windows continued to struggle to make an impact in the US or China, where its share languished at 4.7% and 2.7% respectively.

"You don't have to conquer China and the US to win in the smartphone market, but you do need success in one of them," said Sunnebo, who suggested that Windows Phone needed to gain some momentum very soon "before OS loyalty severely limits the available market".

And while he thought China an easier target, thanks to Nokia's existing presence there, he expected that Microsoft's takeover of the brand meant "it's hard to imagine a change in strategic direction away from the US".

Fears that Apple was putting the iPhone brand at risk by introducing a lower cost model had proved unfounded, as Sunnebo highlighted US data showing the iPhone 5C had an average owner recommendation score of 9.0/10 versus 9.1/10 for the iPhone 5S.

"Both devices attract different customers but crucially each group of owners remains very happy with their choice and are recommending it to others," he said.

Data sourced from Kantar Worldpanel ComTech; additional content by Warc staff