The Swiss bank ordered its traders to not trade in two bonds, a 2014 debt offering by the Venezuelan national oil company PDVSA and Venezuelan government bonds due in 2036, according to a bank memo.
Credit Suisse also directed its staff to not undertake trades issued after June 2017 by the government of Nicolas Maduro.
The bank is also barring transactions with government controlled counterparties, or private Venezuelan entities unless explicitly approved by the bank's reputational risk office.
The moves come one day after the United States slapped economic sanctions on eight Venezuelan politicians linked to the creation of a controversial new assembly loyal to Maduro, including a brother of former president Hugo Chavez.
Washington said the new Constituent Assembly, which was sworn in on August 4th, was created "through an undemocratic process instigated by Venezuelan President Nicolas Maduro's government to subvert the will of the Venezuelan people."