(Reuters) – Hong Kong-based fintech firms AMTD Digital, Magic Empire Global and Top Financial Group tumbled on Tuesday after a meteoric rally this month that was reminiscent of last year’s meme-stock frenzy. The obscure companies have recorded eye-watering gains just days after their US market debuts, with AMTD Digital climbing to as high as $2,555.30 last week from its debut price of $7.80 in July. At its peak, the company’s market valuation dwarfed that of Facebook-owner Meta Platforms. On Tuesday, AMTD Digital was down 45% at $221. Online brokerage Top Financial was trading 14% lower at $17.70, a day after…