What is ACP (Authorized issuer to establish the proof of the customs status of union goods)?

ACP, or Authorised Issuer to Establish the Proof of the Customs Status of Union Goods, is a customs procedure in the European Union (EU) that allows certain approved entities to issue proof of the status of goods as "Union goods". Union goods are goods that have been produced or manufactured in the EU, or have been imported into the EU and have undergone customs procedures, and as such are free to circulate within the EU without further customs duties or taxes.