Corporate partner Marco Compagnoni led the way for the US firm’s team, which also included IP partner Barry Fishley and tax partner Brenda Coleman.
Linklaters acted for Deutsche Post on the sale, with a team led by corporate partner Olivia McKendrick.
The value of the deal remains undisclosed, with the transaction still subject to regulatory clearance, but the combined businesses will produce annual sales in excess of £600m and can be expected to deliver more than 180 million parcels annually.
The tie-up will consolidate HDN’s position as the UK’s largest home delivery and collection service.
“Combining these businesses will enable us to offer our clients a wider variety of propositions and a more efficient service,” said HDN chief executive Brian Gaunt.