A Chinese tech company is now the world's third-largest smartphone maker and the world's most valuable start-up. The company is called Xiaomi Inc. It just raised $1.1 billion and is worth $45 billion. That is more than LG, Motorola and Sony put together. Xiaomi is the world's fastest-growing smartphone maker. Its sales went up by 211 per cent last year. Its market share also went up from 2 per cent to 5 per cent. This success will continue.