The 32-year-old crypto billionaire with a big decision to make

With his baby face, eyeglasses and go-to outfit of T-shirt, jeans and sneakers, Jihan Wu looks more like a geeky teenager than a self-made billionaire.

But thanks to an early foray into cryptocurrencies, the soft-spoken 32-year-old is sitting on what may be one of the industry's largest fortunes.

Wu runs Bitmain Technologies, the world's dominant producer of cryptocurrency mining chips. The Chinese company has been shrouded in secrecy since its founding five years ago, but Wu is gradually lifting the veil - and revealing clues about his personal wealth - as he pursues an expansion beyond the crypto-sphere that may eventually lead to an initial public offering.

In an interview with Bloomberg News, Wu said Bitmain booked $US2.5 billion ($3.3 billion) of revenue last year and that he and co-founder Micree Zhan together own about 60 per cent of the business. While Bitmain has few direct comparables, applying a multiple similar to that of publicly traded chipmakers such as Nvidia and MediaTek would give the company a valuation of about $US8.8 billion. That would make the co-founders' holdings worth a combined $US5.3 billion, according to the Bloomberg Billionaires Index.

Wu, who said he has a smaller stake than Zhan, declined to share details of his net worth, his cryptocurrency holdings and his other personal investments. He has previously said Bitmain is worth $US12 billion. Zhan declined to comment.

Given the uncertainty surrounding digital assets and the limited public information about Bitmain, any estimate of the Beijing-based company's value - and its owners' wealth - inevitably involves a lot of guesswork.