Lenovo Group Ltd reported quarterly revenue that missed analyst estimates, with a decline in smartphone sales curbing investor optimism about the world’s biggest maker of personal computers (PCs) turning into a force in mobile devices. Lenovo’s earnings came at a time of unprecedented competition in China’s smartphone market, with rivals including fast-growing Xiaomi Inc, now the world’s No. 3 handset maker. The Beijing-based company now has a PC market share of 20 percent and has extended its lead over Hewlett-Packard Co (HPQ.N) and Dell Inc [DI.UL], according to IDC research.