The broadest measure of contributor groups is the breakdown into business, labor, and ideological classifications. As in previous cycles, business contributors are by far the largest source of campaign money, though the difference varies depending on the kind of contribution.
Labor is a distant second in overall contributions, with ideological contributions coming in third.
Business contributors whether PACs, individuals or soft money donors favor Republicans. The pro-Republican tilt is about the same for contributions to candidates and to parties. However, the degree of preference varies depending on the kind of contributor. Labor contributes the bulk of its money through PACs to candidates, giving relatively little to national party committees and almost nothing through individuals. Labor contributors overwhelmingly favor Democrats.