By Gabriel Araujo

SAO PAULO Consumer prices in Brazil decelerated more than expected in May, government data showed on Wednesday, with 12-month inflation hitting its lowest level in more than two years and dropping below the 4% mark for the first time since late 2020.

The figures are likely to add weight to calls by President Luiz Inacio Lula da Silva's government and business people for the central bank to lower its key interest rate from the current six-year high of 13.75%.

Annual inflation in Latin America's largest economy hit 3.94% in May, statistics agency IBGE said, below the median forecast of 4.04% in a Reuters poll of economists and the lowest level since October 2020.

Markets responded favorably, with the benchmark stock index Bovespa gaining 1% to trade above 115,000 points for the first time since November 2022, while interest rate futures dropped sharply. The real strengthened 0.1% against the dollar.

Brazil's Planning Ministry said in a statement the lower-than-expected inflation data proved that a disinflationary process was underway in the country, even with unfavorable base effects expected to trigger an uptick starting July.

Credit Suisse economists revised their 2023 inflation forecast to 5.0% from 5.5%, moving forward their call for the start of the monetary easing cycle from September to August, with a 25-basis-point rate cut in sight.

Brazil's central bank has kept its benchmark rate at 13.75% since September to control inflation, triggering criticism from Lula who sees it as hindering economic growth.

Central bank chief Roberto Campos Neto said this week there was still "a problem" with long-term inflation forecasts, with a central bank survey not foreseeing prices to meet the target until beyond 2024, despite being expected to start declining soon.

The central bank currently targets inflation of 3.25% for 2023 and 3% for 2024 and 2025, with a tolerance margin of 1.5 percentage points on either side.

Natalia Gurushina, chief emerging markets economist at VanEck, said the latest consumer prices reading means that Brazil is now on "the final countdown" to rate cuts.

Others, however, took a more cautious approach.

"The fall in inflation last month alongside the strong support for the government's new fiscal framework has strengthened the arguments in favor of interest rate cuts," said Kimberley Sperrfechter, an economist who focuses on Latin America at Capital Economics.

"But we don't think that monetary easing is imminent," she added, forecasting rate cuts to start only in November.

Brazilian consumer prices as measured by the benchmark IPCA index, according to IBGE, rose 0.23% in May from the previous month, an eight-month low. That was also below market forecasts of a rise of 0.33%.

The monthly increase was driven by higher food and housing costs, which were partially offset by a drop in transportation prices, the statistics agency said.

(Reporting by Gabriel Araujo; Editing by Isabel Woodford, Angus MacSwan, Bernadette Baum and Paul Simao)