According to the WSJ:
Some of the big banks were unhappy about the government taking equity stakes, but acquiesced under pressure from Treasury Secretary Henry Paulson in a meeting Monday. During the financial crisis, the government has steadily increased its involvement in financial markets, culminating with a move that rivals the breadth of the government's response to the Great Depression. It intertwines the banking sector with the federal government for years to come and gives taxpayers a direct stake in the future of American finance, including any possible losses.
The government will purchase preferred stock, an equity investment designed to avoid hurting existing shareholders and deterring new ones. Such shares typically don't come with voting rights. They will carry a 5% annual dividend that rises to 9% after five years, according to a person familiar with the matter. By investing in several big firms at once, the government hopes to avoid placing a stigma on any one firm for getting government help.
One question immediately jumps out -- why don't taxpayers get voting rights?