Opensecrets.org recently compiled a list of the political action committees that were the biggest campaign contributors in the current and last election cycles. The following list is a combination of the PACs that were highest contributors to Republicans and to Democrats:
1. Operating Engineers Union $1,977, 975
2. International Brotherhood of Electrical Workers $1,532,650
3. National Association of Realtors $1,456,250
4. AT&T Inc. $1,325,000
5. American Association For Justice $1, 324, 000
6. American Bankers Association $1,297, 270
7. Machinists/Aerospace Workers Union $1,216,500
8. Laborers Union $1,177,500
9. National Beer Wholesalers Association. $1,175,000
10. Sheet Metal Workers Union $1,088,010
