Bank of New York Mellon has fired a London-based currency trader after the bank found that his electronic communications breached its compliance rules, according to a person familiar with the matter.

The dismissal is the first of its kind from this bank, or from any chiefly custody-focused bank, since the global regulatory investigation into currencies-trading practices started early last year, a sign that behaviour is under scrutiny beyond the group of top dealing banks that agreed to pay $4.3 billion in fines on both sides of the Atlantic earlier this month.