How OFAC designates entities and individuals

OFAC adds people, entities, and wallets to the SDN List, and the 50 Percent Rule extends blocking to owned entities.

TL;DR

TL;DR: OFAC designates people and entities by adding them to the SDN List, published via the US Treasury sdn.csv, and also lists crypto wallet addresses; the 50 Percent Rule then extends the block to entities a designated party controls.

The SDN List

The Specially Designated Nationals (SDN) List is how OFAC publishes designations. It currently holds 19,218 names, distributed as the US Treasury sdn.csv file so that screening tools can consume it programmatically. In the crypto context, OFAC also designates specific wallet addresses, with 947 listed wallets tracked in live screening data.

How designations are published

OFAC adds and removes entries over time, which is why the list is not static. Screening data is synced hourly to reflect those changes, so a counterparty screened yesterday may be newly designated today. This is the reason re-screening on every transaction matters, not just at onboarding.

The 50 Percent Rule

A designation does not stop at the named party. The 50 Percent Rule treats any entity owned 50 percent or more by a blocked person as blocked itself, even if that entity never appears on the list by name. Screening ownership structure, not just names, is part of catching these indirect exposures.