General Motors do Brasil Ltda. will likely see flat sales in May compared with April, a company source said Thursday.

As of the last week of May, sales at General Motors' (GM) Brazil unit were keeping pace with April's sales. GM sold 34,318 cars in April, down 16.7% from March, according to the Brazilian Motor Vehicle Manufactureres Association, or Anfavea.

Brazil is GM's third biggest market behind the U.S. and China. It is also the only market outside China that remains a growth story for the troubled Detroit automaker.

Brazil's January to April auto sales are 0.7% lower than the same period last year, when GM and competitors registered record auto sales.

Brazil sold 916,224 cars over the four-month period thanks to a temporary reduction in the IPI industrial production tax. The IPI exemption led to a 7.5% reduction in average sticker prices on new vehicles. The exemption ends on June 30.

-By Kenneth Rapoza, Dow Jones Newswires, 5511-2847-4541, kenneth.rapoza@dowjones.com