Bitcoin continues to plunge as a cryptocurrency sell-off deepens, shaving off gains in share prices that some Hong Kong-listed firms made this year after launching digital asset initiatives.Bitcoin at one point on Tuesday dropped below US$90,000, more than 4 per cent lower than at the start of 2025, after hitting multiple all-time highs this year.The world’s largest cryptocurrency had “underperformed both gold and the Nasdaq amid risk-off sentiment and tight liquidity, exacerbated by the...