Insight - Campaign donations highlight winners, losers in Brazil election

BRASILIA/SAO PAULO (Reuters) - Brazil's financial markets have rallied on the prospect of environmentalist Marina Silva unseating President Dilma Rousseff in next month's election, but political donations show plenty of companies may be wary of a new administration.

    Silva's market-friendly proposals promise relief for oil giant Petrobras, ethanol mills and private banks. But they could also cause headaches for a range of firms facing tougher competition, higher borrowing costs and maybe even more taxes, especially in the energy and auto industries.