The designations will force foreign companies doing business with IRGC to back out in order to avoid US sanctions. The designations are the most serious and powerful set of measures taken by US against Iran to date.
IRGC controls a vast business empire inside Iran and control all strategic imports into the country. The designation will make it hard for IRGC to continue doing business as usual. The Quds Force is the foreign military operations directorate of IRGC. It carries out covert operations in the Middle East and in Europe.