The number of active cryptocurrency users at Bank of America has declined by more than half amid the prolonged rout in the digital-asset market. The bank’s crypto users shrunk to below 500,000 in May from more than 1 million in November 2021, when Bitcoin and some other tokens hit all-time highs. Since then, crypto prices have cratered, with sentiment among fans also souring. Bitcoin has tumbled nearly 60% this year and is trading just above $19,000. The bank said there has been “a grave decl...