The Internal Revenue Service plans to unveil a revamped voluntary disclosure program before December that would cut penalties and aim to close cases within 120 days of a taxpayer finishing the required submission, an overhaul that would extend to unreported cryptocurrency income and gains.

Jarod Koopman, chief of IRS Criminal Investigation and the agency’s chief tax compliance officer, outlined the plan this week at the UCLA Extension Tax Controversy Conference. Digital assets would not get their own track, he indicated; crypto violations would move through the same disclosure machinery used for every other kind of tax noncompliance.

The timing and the size of the penalty reduction are the two details that will decide how much the change…