* Sales rise for third straight month in August
* "Positive" economy stokes automobile demand-Fenabrave
* Fiat leads automobile market, followed by VW, GM, Ford (Adds Brazil credit, automaker ranking, year-ago figures)
SAO PAULO, Sept 1 (Reuters) - Sales of cars, light trucks and buses in Brazil rose for a third straight month in August as low unemployment and a credit boom in Latin America's largest economy stoked demand for automobiles, data showed on Wednesday.
Sales rose 3.5 percent month-on-month in August to 312,812 units and surged 21.2 percent from August of 2009, the Sao Paulo-based association for dealerships said in a statement.
Brazil, Latin America's largest economy, is a major market
for global automakers such as Italy's Fiat SpA
Vehicle sales in the country have boomed in recent months as banks focused on automobile credit to increase their loan portfolios, while rising employment levels meant more Brazilians could afford new automobiles.
"The performance of the automobile industry reflects the positive momentum in the economy," said Sergio Reze, president of Fenabrave, in a statement. "The country is growing. Discounts and loans are also attractive, with lower costs and an abundant volume of funds."
Fiat had a 23.4 percent market share of automobile sales, followed by VW's 22.3 percent, GM's 20.4 percent and Ford's 10.1 percent, Fenabrave said. The Italian automaker also led in sales of light trucks, the association added.
(Reporting by Cesar Bianconi and Elzio Barreto; Editing by Bernard Orr)