The prompt:

Why are OFAC General Licenses for the Iran program denoted by letter, where it seems all other programs’ GLs are numbered?

The response:

Iran GLs aren’t actually lettered as a program-wide convention—the lettering you’re seeing comes from how OFAC issues general licenses within its regulatory parts in the CFR versus as standalone numbered GLs.

The distinction is between two issuance mechanisms:

Codified general licenses (lettered): When a GL is written into the body of the regulations in 31 CFR, it gets a section number with a letter suffix in the §xxx.5xx range. For Iran, these live in the Iranian Transactions and Sanctions Regulations (ITSR, 31 CFR Part 560). So you see things like GL D-2 (the personal communications/internet services GL), GL I, GL J, etc. The letter is essentially the identifier OFAC assigned to that standing authorization, and revisions get numeric suffixes (D, then D-1, then D-2).

Standalone web-published GLs (numbered): Many newer programs—Russia/Ukraine (Part 587/589), Venezuela, etc.—saw OFAC shift to issuing general licenses as separate numbered documents posted to the website (GL 1, GL 2, GL 8K, and so on) rather than codifying each one into the CFR text. These are sequentially numbered per program.

So it’s less “Iran uses letters, everyone uses numbers” and more a function of era and method. Iran is one of the older, heavily-codified programs where the long-standing GLs were embedded in the regulations and carried letter designations. The newer expedited approach—driven partly by how fast Russia-related sanctions had to move after 2022—favored numbered standalone GLs that could be published immediately without going through rulemaking to amend the CFR.

You’ll notice Iran also has numbered GLs in more recent actions (e.g., the post-2018 snapback wind-down GLs were numbered), and some older programs (Cuba’s CACR) similarly use lettered codified GLs. The split tracks codification method and vintage more than the program name itself.