Sen. Charles Grassley, R-Iowa, voted for legislation to overhaul financial regulation two months ago, but he said he will not vote for the final version. According to a statement from Grassley's office, the senator is concerned about compromises reached by congressional negotiators. Specifically, he opposes a scaled-back proposal that would require some banks to spin off their derivatives desks. "I wanted to make the derivatives market transparent," Grassley said. Without Grassley, Democrats likely will have exactly 60 votes, the minimum needed to end debate and move forward with the legislation.