SHANGHAI, Sept 3 (Reuters) - China stocks ended lower on Friday, dented by fresh signs of economic slowdown in the world’s second-largest economy, though losses were capped by upbeat brokerage shares after Beijing floated plans for a new stock exchange. ** At the close, the Shanghai Composite index was down 0.43% at 3,581.73 points, while China’s blue-chip CSI300 index fell 0.54% to 4,843.06 points. ** For the week, the SSEC gained 1.69%, while the CSI300 index was up by 0.33%. ** The smaller Shenzhen index ended 0.58% lower while the start-up board ChiNext Composite index was weaker by 1.17%. However, Shanghai’s tech-focused STAR50 index was closed up 0.1%. ** Sentiment remained weak after a private survey showed activity in China’s services sector slumped into sharp contraction in August, as the Delta variant curbs threatened to derail the recovery in the broad economy. ** But losses were somehow capped by brokerage shares, after China’s President Xi Jinping said the country would set up a stock exchange in its capital, Beijing, to serve small- and medium-sized enterprises. ** Shares of brokerages, including Northeast Securities Co , Dongxing Securities Co and Shenwan Hongyuan Group Co jumped, with investors betting they will benefit from more initial public offerings (IPOs). ** China’s Neeq Component Index, which tracks companies listed on Beijing’s New Third Board, jumped 2.68% at the close. ** The government’s plans to launch a stock exchange knocked down gains in Shenzhen start-up board ChiNext and The Stock Exchange of Hong Kong as some investors fear a rivalry for listing resources is inevitable. ** As of 0730 GMT, HKEX fell 2.69%.