Nio's stock price rose to a historic high after it said that Chinese tech giant Tencent Holdings, the new energy vehicle maker's second-biggest shareholder, has bought more shares. Nio's equity price [NYSE: NIO] reached an all-time high of USD16.44 intraday yesterday in New York, after which it closed 7.6 percent down at USD13.84, with a market cap of USD15.4 billion. This year, the shares have nearly quadrupled in price. Tencent had a 16.3 percent stake in Nio as of July 8, according to the Shanghai-based car company's filing with the US Securities and Exchange Commission yesterday. The Shenzhen-based internet firm has been increasing its holdings lately. Nio issued 60 million American Depositary Shares on June 9 at a price of USD5.97 and Tencent bought 1.7 million of them, spending USD10 million. It had a 15.1 percent stake after that.