BEIJING/SHANGHAI, May 19 (Reuters) - China shares ended lower on Wednesday after three straight sessions of gains, dragged down by property and energy firms, while digital currency-related stocks fell after Beijing banned financial and payment companies from the cryptocurrency business. ** At the close, the Shanghai Composite index was down 0.51% at 3,510.96, while the blue-chip CSI300 index was down 0.3%. ** The energy sector sub-index fell 1.61%, and the real estate index dropped 1.65%. ** The smaller Shenzhen index ended up 0.12% and the start-up board ChiNext Composite index was higher by 0.796%. ** Investors are betting on the increasing momentum of A shares and searching for opportunities in consumer blue-chips and new energy vehicles firms, said Yang Delong, an investment manager at First Seafront Fund Management Co. ** Trading in the mainland market is volatile, Yang said, citing relative low valuations for A-shares and Hong Kong stocks amid surging global equities. ** China has banned financial institutions and payment companies from providing services related to cryptocurrency transactions, and warned investors against speculative crypto trading. ** Hong Kong markets were closed for a holiday. ** Around the region, MSCI’s Asia ex-Japan stock index was weaker by 0.38%, while Japan’s Nikkei index closed down 1.28%. (Reporting by Cheng Leng in Beijing, Luoyan Liu and Andrew Galbraith in Shanghai; Editing by Rashmi Aich) Our Standards: The Thomson Reuters Trust Principles.