Cryptocurrency exchange Kraken has been ordered by a judge to provide a wide swath of information about its users to the Internal Revenue Service for the agency’s investigation of underreported tax liability.

Bloomberg reported that the IRS has said it wants information on Kraken accounts that did at least $20,000 of cryptocurrency trading in any single year, from 2016 to 2020. Kraken had called the agency’s summons an “unjustified treasure hunt,” arguing it went well beyond the boundaries set in a similar fight with Coinbase about six years ago. 

Friday’s ruling siding with the government comes amid a deepening US crackdown on cryptocurrency. The Securities and Exchange Commission this month filed separate lawsuits accusing Coinbase of running an illegal exchange and alleging that Binance.US mishandled customer funds, misled investors and regulators, and broke securities rules. 

The IRS didn’t win everything it was seeking from Payward Inc., the San Francisco-based company established in 2011 to operate Kraken, but US Magistrate Judge Joseph Spero directed the company to turn over users’ names, birth dates, taxpayer identification numbers, addresses, phone numbers, email addresses, some documents and transactional ledgers. 

The IRS “has a legitimate purpose for seeking the materials,” the judge wrote, namely to “determine the identity and correct federal income tax liability” for users in the designated time period.