Chinese smartphone manufacturer Xiaomi has raised another $1bn (£640m) in funding, placing its current valuation at $45bn, a huge increase from its previous valuation of $10bn in August 2013.

The valuation, which was reported by the Wall Street Journal, has not been confirmed by Xiaomi, which this year became the third-largest smartphone manufacturer in the world, despite remaining largely focused in the Asian market.

The company sold around 19m phones in 2013, and hopes to more than double that figure to 40m units in 2014, a target it appears to be on track to hit.

This year has seen the company expand, with a focus on building operations in emerging markets like Southeast Asia, Brazil, Mexico and India where it will no doubt aim to recreate the success it has had in China thanks to its cheap handsets and focus on online marketing. However, it suffered a setback recently when it was barred from selling in India following a patent claim by Ericsson.

There has also been confusion over how much money the company has made. In early November, reports in the Wall Street Journal suggested the company had doubled its profits between 2012 and 2013, but a later report based on a regulatory filing claimed that the company had made only $56m in net profit in 2013.