SINGAPORE, Sept 13 (Reuters) - Singapore"s DBS Group (DBSM.SI) expects to double the number of members on its new platform for cryptocurrency trading to 1,000 by end-December and grow this by 20-30% annually for the next three years as digital tokens gain acceptability. In an interview, DBS"s senior executives said DBS Digital Exchange, set up in December as a members-only bourse, is seeing robust demand from corporate investors, accredited individuals and investment firms that manage the fortunes of wealthy families. "We are growing very rapidly. Investors are gradually exploring cryptocurrencies and digital assets," said Eng-Kwok Seat Moey, head of capital markets at DBS, Southeast Asia"s largest bank by assets, and chairperson of the exchange. DBS"s foray in the crypto business come after its CEO Piyush Gupta steered the bank to invest billions of dollars to upgrade its technology infrastructure over the past eight years as it embraced cloud computing and digitised its services. DBS Digital Exchange bills itself as the world"s only bank-backed full service digital bourse - offering cryptocurrency trading, asset tokenisation and digital custody services, in a crypto sector where investor trust is still low. Soaring popularity of cryptocurrencies has posed a problem for mainstream banks as they try and balance clients" interest in digital coins with regulatory concerns about their risks. A unit of Standard Chartered (STAN.L)is setting up a joint venture to establish a cryptocurrency brokerage and exchange platform in Britain and Europe, while HSBC (HSBA.L) said it has no plans to offer digital currencies to customers. Eng-Kwok said DBS" position as one of the biggest wealth managers in Asia and its expertise in originating deals in capital markets would help it attract users and grow trading volume. The move comes at a time when DBS, like other banks, is looking to boost fee-based income as net interest income decreases amid low interest rates. Eng-Kwok said the bourse hopes to list at least half a dozen security tokens by end-2022. Singapore"s central bank brought crypto businesses under a new regulatory framework that came into effect in January 2020. DBS" brokerage arm has received an-principle approval under the new regime, which will allow it to directly support asset managers and companies to trade in digital payment tokens through the bourse. The Singapore Exchange (SGXL.SI) has a 10% stake in the bourse. "Having mainstream banks helps foster an environment where settlement risk is minimal and there are safeguards in place for custody of user deposits and security of transactions," said Ganesh Viswanath-Natraj, assistant professor of finance at Warwick Business School in Britain. Last week, Binance, one of the world"s largest cryptocurrency exchanges, said it will restrict its services in Singapore days after the central bank told it to stop offering payment services. DBS Digital Exchange offers trading services between bitcoin, bitcoin cash, ethereum and XRP, and U.S., Singapore, Hong Kong dollars and the yen. "Our aim was to create a platform that could serve the entire digital asset value chain, from deal origination to tokenisation, listing, trading, and custody – all within a trusted and regulated bank franchise," said Kwee Juan Han, DBS" group head of strategy and planning. Han said a trend of companies exploring fundraising options through tokenised assets, and growing interest by private investors to expand the share of digital assets in portfolios offered DBS a timely opportunity to launch the bourse. He said DBS expects its new businesses, including the digital exchange and a carbon exchange to bring in total revenue of S$350 million ($260 million) by the end of next year. ($1 = 1.3432 Singapore dollars)