* SSEC -0.3 pct, CSI300 -0.5 pct, HSI -0.5 pct
* HK->Shanghai Connect daily quota used -4.3 pct, Shanghai->HK daily quota used 4.7 pct
* FTSE China A50 -0.6 pct, BNY Mellon ADR China Select Index -1.6 pct
SHANGHAI, March 20 (Reuters) - Stocks in China and Hong Kong fell early on Tuesday, tracking losses on Wall Street, where concerns over increased regulation of large technology companies led to shares of Facebook plunging overnight.
** Facebook shares tumbled 6.8 percent as Chief Executive Mark Zuckerberg faced calls from both U.S. and European lawmakers to explain how a consultancy that worked on U.S. President Donald Trump's election campaign gained access to data on 50 million Facebook users.
** Investors also worried about the potential for a trade war after Trump imposed tariffs on steel and aluminium.
** At 04:06 GMT, the Shanghai Composite index was down 0.26 percent at 3,270.82, and the blue-chip CSI300 index was 0.48 percent lower at 4,054.64.
** Chinese H-shares listed in Hong Kong fell 0.93 percent at 12,542.44, while the Hang Seng Index was down 0.54 percent at 31,344.20.
** The smaller Shenzhen index was down 0.55 percent, while the start-up board ChiNext Composite index was weaker by 0.06 percent.
** The Trump administration is expected to unveil up to $60 billion in new tariffs on Chinese imports by Friday, targeting technology, telecommunications and intellectual property, two officials briefed on the matter said Monday.
** U.S. businesses have been alarmed, with several large U.S. retail companies, including Walmart Inc and Target Corp , on Monday urging Trump not to impose massive tariffs on goods imported from China.
** Around the region, MSCI's Asia ex-Japan stock index was weaker by 0.31 percent, while Japan's Nikkei index was down 0.73 percent.
** The yuan was quoted at 6.3264 per U.S. dollar, 0.07 percent firmer than the previous close of 6.3308.
** The largest percentage gainers on the main Shanghai Composite index were Guodian Nanjing Automation Co Ltd up 10.1 percent, followed by Guizhou Yibai Pharmaceutical Co Ltd gaining 10.03 percent and Beijing AriTime Intelligent Control Co Ltd up by 10.02 percent.
** The largest percentage losers on the Shanghai index were Heilongjiang Interchina Water Treatment Co Ltd down 6.41 percent, followed by Cultural Investment Holdings Co Ltd losing 6.36 percent and Zhonglu Co Ltd falling by 5.46 percent.
** The top gainers among H-shares were CSPC Pharmaceutical Group Ltd up 10.4 percent, followed by China Gas Holdings Ltd gaining 4.74 percent and Huaneng Power International Inc up by 1.37 percent.
** The three biggest H-shares percentage decliners were Byd Co Ltd which has fallen 2.70 percent, China Vanke Co Ltd which lost 2.7 percent and New China Life Insurance Co Ltd down by 2.2 percent.
** About 8.25 billion shares have traded so far on the Shanghai exchange, roughly 45.9 percent of the market's 30-day moving average of 17.96 billion shares a day. The volume traded was 13.80 billion as of the last full trading day.
** As of 04:06 GMT, China's A-shares were trading at a premium of 25.94 percent over the Hong Kong-listed H-shares.
** The Shanghai stock index is below its 50-day moving average and its 200-day moving average.
** The price-to-earnings ratio of the Shanghai index was 14.91 as of the last full trading day, while the dividend yield was 2 percent.
** So far this week, the market capitalisation of the Shanghai stock index has risen by 0.24 percent to 29.29 trillion yuan.
** In Hong Kong, the sub-index of the Hang Seng index tracking energy shares rose 0.3 percent, while the IT sector fell 0.3 percent. The top gainer on Hang Seng was Sunny Optical Technology Group Co Ltd up 3.94 percent, while the biggest loser was Hong Kong Exchanges and Clearing Ltd which was down 1.81 percent.
(Reporting by Samuel Shen and John Ruwitch; Editing by Biju Dwarakanath)