Pay your taxes on bitcoin…or else.

Late last year, the Internal Revenue Service persuaded a federal judge to require Coinbase, a San Francisco-based digital-currency wallet and platform with about 20 million customers, to turn over customer information. Driving the IRS’s decision was its belief that few bitcoin investors appear to be paying taxes due on sales. The court order is one of the agency’s first moves as it clamps down on cryptocurrency scofflaws.

By March 16, the IRS will have data on about 13,000 Coinbase account holders who bought, sold, sent or received digital currency worth $20,000 or more between 2013 and 2015. The data include the customer’s name, taxpayer identification number, birth date and address, plus account statements and the names of counterparties.

Criminal tax lawyers expect the IRS will act on the information and high-profile cases will follow.

Some cryptocurrency holders are now disclosing past tax lapses to avoid potential criminal prosecution.