The agency will serve as Western Union's communication agency of record across Europe and the Commonwealth of Independent States.
APCO won the business following a competitive pitch process.
The brief focuses on corporate affairs support, including media relations and thought-leadership efforts as well as associated public affairs and stakeholder management.
APCO will coordinate the firm's comms activity across a number of European markets, including the UK, France, Spain, Italy and the Benelux countries, and will work with incumbent agencies in other territories.
Angela Heng, vice president of corporate affairs for Western Union in Europe, the Middle East, Africa and Asia-Pacific, said: ‘Corporate communications is one of Western Union's key priorities, and we will continue maintaining a constructive dialogue with our diverse stakeholder base.'
APCO is also assisting Western Union with the integration of newly acquired agent network FMT, formerly the money transfer business of Fexco.