| DEMOCRATIC STATE CENTRAL COMMITTEE OF MARYLAND | $28K | 9 | 2010, 2014, 2006, 2012, 2022 |
| ENGINEERS POLITICAL EDUCATION COMMITTEE (EPEC)/INTERNATIONAL UNION OF OPERATING ENGINEERS | $23K | 10 | 2010, 2014, 2006, 2012, 2008 |
| CARPENTERS LEGISLATIVE IMPROVEMENT COMMITTEE UNITED BROTHERHOOD OF CARPENTERS AND JOINERS | $20K | 10 | 2010, 2014, 2006, 2012, 2008 |
| AMERICAN POSTAL WORKERS UNION COMMITTEE ON POLITICAL ACTION | $20K | 15 | 2010, 2006, 2020, 2016, 2018, 2022, 2008 |
| NATIONAL ASSOCIATION OF REALTORS POLITICAL ACTION COMMITTEE | $19K | 13 | 2010, 2006, 2012, 2008 |
| NEA FUND FOR CHILDREN AND PUBLIC EDUCATION | $19K | 16 | 2010, 2024, 2014, 2006, 2016, 2012, 2018, 2008 |
| INTERNATIONAL BROTHERHOOD OF ELECTRICAL WORKERS POLITICAL ACTION COMMITTEE | $19K | 9 | 2010, 2014, 2006, 2016, 2008 |
| AMERICAN FEDERATION OF TEACHERS, AFL-CIO COMMITTEE ON POLITICAL EDUCATION | $15K | 3 | 2010, 2006, 2008 |
| AIR LINE PILOTS ASSOCIATION PAC | $14K | 5 | 2010, 2006, 2008 |
| AMERICAN FEDERATION OF STATE COUNTY & MUNICIPAL EMPLOYEES P E O P L E | $14K | 6 | 2010, 2006, 2008 |