Venezuela’s state-owned oil firm PDVSA has tightened the prepayment rules for its oil after a review of contracts, demanding now cargoes be paid in cash or in goods and services that should be received before loadings can take place, Reuters reported on Monday, quoting PDVSA documents it had seen.

The new models set deadlines of less than 30 days for completing bank transfers or settling outstanding debt balances. In cases of swaps where the related oil sale exceeds the value of the goods or services, Venezuela must receive any outstanding balance in kind before the state will assign the next cargo, one of the documents showed.