Not long after buying and publicly consuming a $6.2m banana as part of an artworld stunt, Chinese crypto entrepreneur Justin Sun made another eye-catching purchase, investing $30m ($23.5m) into a cryptocurrency firm called World Liberty Financial.

The company had foundered since its October launch, investors seemingly leery of its prospects and its terms.

But it boasted a potentially enticing feature: the chance to do business with a firm partnering with and promoted by none other than Donald Trump.

Mr Sun’s investment tipped the company over the threshold that allowed the president-elect to begin profiting from the venture. Trump and his family are now in the position to collect roughly $20m – and potentially far more.

Mr Sun,…