IPC members represent postal operators from Europe, North America and the Asia-Pacific region. Collectively, their operations deliver 80% of global mail volumes – more than 336bn letters each year.

IPC Shareholding Members are allocated a minimum number of shares based on their total addressed mail volumes (i.e., total letter mail handled and delivered inside and outside the organisation's home country, excluding unaddressed mail and newspapers but including magazines). All IPC members should have a universal service obligation for the provision of mail services although the Board is authorised to admit members without such an obligation. (A full explanation of Membership Duties and Responsibilities, as well as the requirements for applying for membership, can be found in IPC's General Terms and Conditions and Articles of Association.)