After pleading guilty to violating US anti-money-laundering rules, a top employee at cryptocurrency derivatives trading exchange BitMEX was sentenced to 12 months probation in federal court in Manhattan on Wednesday. Gregory Dwyer, a 39-year-old Australian native, was one of the exchange’s first employees and its former head of business development. Prosecutors in the United States charged Mr. Dwyer and the exchange’s founders with failing to implement anti-money-laundering and know-your-customer programmes, as required by US law. In August, he pleaded guilty to one count of violating the Bank Secrecy Act. Mr. Dwyer also agreed to pay $150,000 in fines as part of the plea agreement.