The formula was introduced on January 1 and combines price increases with the phasing out of subsidies.
Work on the Brazilian petrochemical project was stalled in October 2015 after local prosecutors said they were investigating alleged contract irregularities as part of their Lava Jato corruption probe.
The exception to the new 80% policy will be for credit given to municipalities for reconstruction after natural disasters, which will keep its 100% limit.
State governors have met with the finance and energy ministers to study ways of reducing fuel prices.
Apart from the political backlash, Wood Mackenzie identifies further risks associated with the upcoming liberalization of the market.
In its most recent business plan, Brazil's Petrobras reduced by more than 70% investments in fuel logistics infrastructure. Sergio Bandeira de Mello, president of the country's LPG distributors' association, spoke to BNamericas about how distributors are dealing with the change in scenario.
Mexico's president says the increase in fuel prices that has led to nationwide protests was inevitable.
The main idea is to get rid of five taxes and replace them by a single tax to make life easier for both companies and the government.