Once a country has reached certain threshold of poverty, elections can get very sensitive to bought support. Maybe not direct, checked "money for vote" transactions, but gaining "genuine" support by being generous (genuine as in the voters don't realize that they are being manipulated).

And if toxic investors are clever, they might even support every major candidate a little: they have already reached their goal if the eventual winner believes that his secret supporter was acting as kingmaker. Might be much cheaper in total than actually forcing a result with money.