The world's biggest cryptocurrency asset manager said on Tuesday it was seeing efforts to shift bitcoin production to North America from China, which dominates digital coin mining. Barry Silbert, founder of New York-based Grayscale Investments, made the observation in an online presentation to investors, without saying why the shift was occurring. Many mainstream investors such as pension funds or asset managers have been reluctant to embrace bitcoin, concerned at its volatility, security breaches and lack of transparent markets.

Bitcoin, heavily favoured by enthusiasts and retail investors since it emerged more than a decade ago, has gained increasing interest from hedge funds and trading firms. Many are drawn to its potential for high returns in an era of rock-bottom interest rates. China's bitcoin miners control around two-thirds of the crypto network's processing power, research last year estimated.

That dominance has allowed Chinese miners to produce greater numbers of coins, and has also stoked demand for mining gear produced in the country. Bitcoin miners - typically firms that run collections of highly-powered computers hooked up to cheap, plentiful electricity - compete against others in the bitcoin network to solve complex maths puzzles and earn new coins.

At Tuesday's bitcoin price of around $10,300, miners produce bitcoin worth around $6.7 billion every year. Chinese firms such as Bitmain have become among the world's biggest miners and manufacturers of bitcoin mining hardware. Another maker, Canaan, launched an initial public offering in November, but got a lukewarm investor response.