BRASILIA, July 30 (Reuters) - Brazil's central government posted a primary budget deficit of 8.206 billion reais ($2.43 billion) in June, the biggest gap for that month in the 18 years such data has been compiled, according to treasury data released on Thursday.
The central government account, which covers federal ministries, the central bank and social security, posted a primary deficit of 8.501 billion reais in May.
A sharp drop in tax revenues as the economy contracts forced the government last week to slash the public sector's primary surplus targets for this and the next two years. The less ambitious targets sparked a sell-off of Brazilian assets and prompted Standard & Poor's to threaten to strip the country of its investment-grade rating.
The 2015 central government primary surplus target was cut to 5.8 billion reais from 55.3 billion reais originally, or the equivalent of only 0.1 percent of gross domestic product.
The deficit in June was the widest for that month since the treasury started to collect the data in 1997. ($1 = 3.3794 Brazilian reais) (Reporting by Luciana Otoni; Writing by Alonso Soto; Editing by James Dalgleish)