In this article Matthew Parker KC considers the remedy of subrogation where money is provided by mistake. The context is Citibank’s mistaken US$500m payment to lenders which has now, on appeal, been held not to have discharged Revlon’s debt. This follows Matthew’s earlier article in the July/August 2021 edition, ‘Payments by mistake: when will the discharge of an existing debt be a defence to a claim for repayment’ (2021) 7 JIBFL 457.