The "IMSI Assignment and Management Guidelines and Procedures" contains the guidelines and procedures for the assignment and use of International Mobile Subscriber Identities (IMSIs) in the United States with consideration given to other North American Numbering Plan (NANP) countries.
The document is updated and revised by the IOC as the need arises. Revisions to the guidelines are effective upon publication by the IOC Secretariat. IMSI Assignment and Management Guidelines and Procedures (Version 15; March 2014)
All applications for IMSIs are submitted and processed through the IMSI-A website.
For your convenience the following are available for download separate from the full Guidelines above:
Link to ATIS Editorial Guide