Can OFAC sanction a crypto exchange?

Yes. OFAC can and has designated cryptocurrency exchanges and imposed penalties for sanctions violations.

TL;DR

TL;DR: Yes. OFAC has designated cryptocurrency exchanges on the SDN List and pursued enforcement against others. Exchanges face the heaviest OFAC exposure in crypto.

Why exchanges are targeted

Exchanges sit at the chokepoint where fiat and crypto meet, and where large volumes of value move. That makes them a priority for enforcement. OFAC applies strict liability, so an exchange can violate without intent. The volume and the on-ramp position both draw scrutiny.

What enforcement looks like

OFAC can add an exchange to the SDN List, which blocks US persons from dealing with it. It can also impose civil penalties, starting at $356,000 per violation. The 50 Percent Rule extends restrictions to entities majority owned by a blocked exchange, so affiliates are caught too.

What exchanges must do

Screen every customer and wallet before onboarding and on every transaction. Use a live SDN list synced hourly so newly designated parties are caught immediately. Log every screen, and block on match. For an exchange, a missed designation is a legal event, not a data gap.

The penalty exposure

Civil penalties for sanctions violations start at $356,000 per violation, and a busy exchange can rack up many violations before a gap is found. That is why continuous, logged screening matters more than a one-time onboarding check. Each transaction that skips the screen is a potential separate violation, so the count can compound quickly.