New York Attorney General Eric Schneiderman’s Investor Protection Bureau sent letters and questionnaires this week to 13 cryptocurrency trading platforms seeking information on operational controls, money laundering and privacy practices, but at least one company said it won’t comply, and a financial services regulation expert called the attorney general’s action “extraordinary.”

The companies receiving the questionnaires included Coinbase; Gemini Trust Co.; bitFlyer USA Inc.; and 10 others. The Attorney General’s Office imposed a May 1 deadline for compliance.