The closest links of the U.S. IC to other foreign intelligence agencies are to Anglophone countries: Australia, Canada, New Zealand, and the United Kingdom. There is a special communications marking that signals that intelligence-related messages can be shared with these four countries. An indication of the United States' close operational cooperation is the creation of a new message distribution label within the main U.S. military communications network. Previously, the marking of NOFORN (i.e., No Foreign Nationals) required the originator to specify which, if any, non-U.S. countries could receive the information. A new handling caveat, USA/AUS/CAN/GBR/NZL Five Eyes, used primarily on intelligence messages, gives an easier way to indicate that the material can be shared with Australia, Canada, United Kingdom, and New Zealand.

Which four countries can share communications with the U.S. IC?