美股中概股盘前涨跌互现，携程跌1%

Group 1 - The core viewpoint of the article indicates mixed performance among Chinese concept stocks in the US pre-market trading, with NIO showing a slight increase while Alibaba, JD.com, Ctrip, and Manbang experienced declines [1][2] Group 2 - NIO's stock increased by 0.6% in pre-market trading [1] - Alibaba's stock decreased by 0.2% in pre-market trading [1] - JD.com, Ctrip, and Manbang all saw a decline of 1% in their stock prices [1]