BRASILIA, Oct 21 (Reuters) - Four senior Brazilian Treasury officials resigned on Thursday amid signs the government is looking to lift a constitutional spending cap, hammering Brazil"s stocks and currency while driving up interest rate futures. With Bolsonaro"s popularity slipping and headlines focused on a Senate inquiry calling for criminal charges based on his handling of the pandemic, the president has pushed for more government spending ahead of next year"s election. read more Economy Minister Paulo Guedes said late on Wednesday that the government may try to exempt 30 billion reais ($5.3 billion) of spending from its fiscal ceiling in order to boost welfare spending at President Jair Bolsonaro"s request. read more In a sign of the widening schism over fiscal issues, Brazil"s two most senior Treasury officials and their two deputies submitted their resignations on Thursday "for personal reasons," according to a statement from the Economy Ministry. Allies in Congress have moved swiftly to open space for more election-year spending. Lawmaker Hugo Motta offered on Thursday to shift the calendar for an annual adjustment of the spending cap as part of a constitutional amendment he is sponsoring to parcel out payments of the government"s court-ordered debts. Taken together, the measures would open space for nearly 96 billion reais of additional spending next year, tweeted Felipe Salto, head of the Senate"s fiscal watchdog IFI, citing preliminary calculations. In a speech on Thursday, Bolsonaro also promised some 750,000 truckers relief to offset rising diesel prices, without giving details. He repeated a vow to more than double payouts from Brazil"s main welfare program in a fiscally "responsible" way, although markets shrugged off his assurances. read more Brazil"s benchmark stock index (.BVSP) plunged nearly 5% in Thursday trading, finishing down 2.8% at its lowest close since November. The real weakened nearly 2%, testing levels near 5.7 to the U.S. dollar for the first time since April. Markets closed before the Economy Ministry announced the exit of Treasury officials Bruno Funchal and Jeferson Bittencourt, two of the most senior aides to Guedes on fiscal policy. Interest rate futures showed bets on even more aggressive rate increases by the central bank to contain inflation already running in double digits over the past 12 months. JPMorgan analysts shifted their call for upcoming monetary policy meetings, forecasting that the central bank will hike rates by 125 basis points next week and again in December instead of its prior outlook for continued 100-basis-point increases. The proposal to exempt additional welfare spending from the spending cap "is already jeopardizing the credibility of the fiscal sustainability," they wrote, adding that policymakers may turn even more aggressive with a 150-basis-point hike next week. The JPMorgan analysts warned of fresh stimulus "backfiring" by forcing the central bank to tighten financial conditions, threatening a forecast for the economy to grow 0.9% next year. ($1 = 5.6870 reais)