No. Each OFAC sanctions program is based on different underlying authorities and foreign policy and national security goals, so the prohibitions imposed vary between programs. Most programs block the property and interests in property of specific individuals and entities. Certain programs do not require blocking of any property; instead, they generally prohibit U.S. persons from engaging in certain trade or financial transactions and other dealings with specified persons or jurisdictions.
When a particular sanctions program prohibits transactions but does not impose blocking requirements, an institution may be required to reject, rather than block, the prohibited transactions. As with blocked transactions, rejected transactions must also be reported to OFAC through the OFAC Reporting System (ORS), within 10 business days, pursuant to 31 CFR § 501.604. To register for access or to log in to ORS, please see the OFAC Reporting System page on OFAC's website.
For more information on rejecting transactions, see FAQ 36. For information on specific prohibitions, authorizations, or exemptions under a particular OFAC sanctions program, please see the relevant OFAC implementing regulations and the Sanctions Programs and Country Information page on OFAC's website.