Accountants and lawmakers are urging standard-setters to fill a void and write concrete rules telling companies how to account for bitcoin and other cryptocurrency assets.

The assets, for which there are no binding US accounting requirements, have drawn regulators’ interest after sharp swings in recent months and investments by companies such as electric-car maker Tesla and payment provider Square. Bitcoin, which rose to a record of $63,381 in April, has roughly halved in value since then, mirroring volatility in other digital currency assets.