BEIJING -- Stocks in mainland China stumbled badly Thursday after weeks of gains, with the Shanghai Composite Index falling 4.8% to 1656. In Hong Kong, the Hang Seng fell 1.3% to 16,305.Before Thursday's loss, as of the July 12 close in Shanghai, the index had shot up 12% in just one month. Even after factoring in Thursday's declines, the Shanghai Comp can still claim a 6.4% one-month gain. China shares in New York were mixed in Wednesday trading. KongZhong ( KONG) lost 2.8% to $6.85 and Baidu ( BIDU) fell 1.3% to $85. But others saw green. The9 ( NCTY) rose 6.9% to $25.18. Hurray ( HRAY) gained 2.3% to $5.37 after announcing a partnership deal with Viacom subsidiary MTV Music Television China. CEO QD Wang said Hurray, which lets cell phone users pay to download ringtones, games and pictures, has a customer base with "remarkably similar demographics" to MTV's audience. Spokesperson Phoebe Meng said Hurray customers are generally aged 12 to 35 and predominantly women. MTV viewers will be able to use Hurray's services on their mobile phone to do things like listen to music clips or vote for their favorite singer. Among other joint projects, Hurray will collaborate with MTV on "Star File," an MTV show featuring a hostess interviewing film stars and singers that lets audience members send mobile phone messages to request information about their favorite stars. An MTV-sponsored English learning program will let cell phone users interact by making suggestions about what they'd like to study in future shows -- naming popular English-language songs they'd like to learn the lyrics of, for example. Hurray also plans to set up a mobile phone-based "club" that will let its customers talk with and ask questions of recording artists on MTV. MTV's influence in China is limited, however, since as a foreign channel it's only allowed to broadcast for part of the day. Foreign content is restricted to less than 50% of television programming for shows that reach most Chinese audiences.