* HK->Shanghai Connect daily quota used 3.7%, Shanghai->HK daily quota used 3.6% * HSI -0.3%, HSCE +0.0%, CSI300 -0.1% * FTSE China A50 +0.3% July 6 (Reuters) - Hong Kong stocks closed lower on Tuesday, as healthcare firms slumped in line with their mainland peers on worries over lofty valuations. ** At the close of trade, the Hang Seng index was down 70.64 points or 0.25%, at 28,072.86. The Hang Seng China Enterprises index fell 0.04% to 10,269.6. ** The sub-index of the Hang Seng tracking energy shares dipped 0.1%, while the IT sector rose 0.62%, the financial sector ended 0.5% higher and the property sector dipped 0.27%. ** The Hang Seng healthcare index fell the most, tumbling 5.1%, tracking losses in their mainland-listed peers, where the CSI300 healthcare index declined 3.8%. ** Jinxin Fertility Group Ltd, Shanghai Fosun Pharmaceutical Group Co Ltd, WuXi Biologics, and Hangzhou Tigermed Consulting slumped between 8.3% and 10.6%. ** The top gainer on the Hang Seng was Haidilao International Holding Ltd, which gained 4.16%, while the biggest loser was WuXi Biologics (Cayman) Inc, which fell 8.41%. ** The Hang Seng tech index extended decline to finish 0.9% lower, amid continued worries over regulations. ** China’s antitrust regulator is set to formally block Tencent Holdings Ltd’s plan to merge the country’s top two videogame streaming sites, Huya and DouYu, three people familiar with the matter told Reuters. ** China’s main Shanghai Composite index closed down 0.11% at 3,530.26 points, while the blue-chip CSI300 index ended down 0.05%. ** Around the region, MSCI’s Asia ex-Japan stock index was firmer by 0.06%, while Japan’s Nikkei index closed up 0.16%. ** The yuan was quoted at 6.4628 per U.S. dollar at 08:22, 0.02% firmer than the previous close of 6.4639. ** At close, China’s A-shares were trading at a premium of 39.53% over Hong Kong-listed H-shares. (Reporting by the Shanghai Newsroom; Editing by Rashmi Aich) Our Standards: The Thomson Reuters Trust Principles.