According to the United States Office of Foreign Assets Control (OFAC), the Venezuelan government has until the end of April 2019 to sell crude oil to the United States without sanctions. After this deadline, penalties will be imposed on the state-run oil producer PDVSA or on any other company which is more than 50% controlled by the Venezuelan government, in an attempt to force the current president to relinquish control to the legislative assembly president. Besides, any offshore (i.e. not based in the US) firm that is purchasing crude oil from PDVSA will have to wind down its purchases by that date if it is using US dollars to buy it or if it is closing a transaction via an US-based financial institution.
The major US importers of Venezuelan crude oil are the American oil and gas companies Valero and Chevron. As sanctions against PDVSA ripple through the market, a loss of access to Venezuelan oil could result in a challenge for both of them.
Besides, PDVSA has one subsidiary in the US: the oil refiner Citgo, which owns three major refining complexes in the US with a total refining capacity of 750,000 bbl/d. The affiliate's future is uncertain with the looming sanctions and various options are currently being considered in order to protect its operations and keep them running. The increasingly difficult situation could prompt PDVSA's creditor Rosneft to start encroaching Citgo to claim repayments. The Russian company previously extended a loan to PDVSA, which used 49.9% in Citgo as collateral for that loan, and if it defaults on the loan, Rosneft could claim that stake in Citgo.