| NATIONAL ASSOCIATION OF REALTORS POLITICAL ACTION COMMITTEE | $376K | 45 | 2002, 1996, 1994, 2006, 1992, 1998, 2004, 2008, 2000 |
| SEIU COPE (SERVICE EMPLOYEES INTERNATIONAL UNION COMMITTEE ON POLITICAL EDUCATION) | $280K | 22 | 2002, 1996, 1994, 2006, 1992, 1998, 2004, 2008, 2000 |
| AMERICAN ASSOCIATION FOR JUSTICE POLITICAL ACTION COMMITTEE (AAJ PAC) | $69K | 33 | 2002, 1996, 1994, 2006, 1992, 1998, 2004, 2008, 2000 |
| MACHINISTS NON PARTISAN POLITICAL LEAGUE OF THE INTERNATIONAL ASSOCIATION OF MACHINISTS & AEROSPACE WORKERS | $65K | 18 | 2002, 1996, 1994, 2006, 1992, 1998, 2004, 2000 |
| UAW - V - CAP (UAW VOLUNTARY COMMUNITY ACTION PROGRAM) 'INT'L UNION UNITED AUTOMOBILE AEROSPACE & AGRICULTURAL IMPLEMENT WORKERS OF AMERICA UAW | $62K | 31 | 2002, 1996, 1994, 2006, 1992, 1998, 2004, 2008, 2000 |
| DEMOCRATIC STATE CENTRAL COMMITTEE OF MARYLAND | $61K | 22 | 2002, 1994, 1992, 1998, 2004, 2000 |
| AMERICAN FEDERATION OF STATE COUNTY & MUNICIPAL EMPLOYEES P E O P L E | $61K | 35 | 2002, 1996, 1994, 2006, 1992, 1998, 2004, 2008, 2000 |
| D.R.I.V.E. - DEMOCRAT, REPUBLICAN, INDEPENDENT VOTER EDUCATION (THE PAC OF THE INTERNATIONAL BROTHERHOOD OF TEAMSTERS) | $58K | 22 | 2002, 1996, 1994, 2006, 1992, 1998, 2008, 2000 |
| UNITED FOOD AND COMMERCIAL WORKERS INTERNATIONAL UNION ACTIVE BALLOT CLUB | $54K | 38 | 2002, 1996, 1994, 2006, 1992, 1998, 2004, 2008, 2000 |
| NATIONAL ASSOCIATION OF REALTORS | $53K | 3 | 2006, 2008 |