| 2024 | The Esplanade Association Inc | 990 | Director | 1 | $0 | $0 | View return |
| 2024 | Boothbay Region Student Aid Fund Inc. | 990 | President | 1 | $0 | $0 | View return |
| 2023 | Boothbay Region Education Foundation | 990 | Trustee | 1.5 | $0 | $0 | View return |
| 2023 | The Esplanade Association Inc | 990 | Director | 1 | $0 | $0 | View return |
| 2023 | The American College Health Foundation Incorporated | 990 | Director | 1 | $0 | $0 | View return |
| 2023 | Boothbay Region Student Aid Fund Inc. | 990 | President | 1 | $0 | $0 | View return |
| 2022 | The American College Health Foundation Incorporated | 990 | Director | 1 | $0 | $0 | View return |
| 2022 | Boothbay Region Student Aid Fund Inc. | 990 | President | 1 | $0 | $0 | View return |
| 2022 | Boothbay Region Education Foundation | 990 | Trustee | 1.5 | $0 | $0 | View return |
| 2021 | Boothbay Region Student Aid Fund Inc. | 990 | President | 1 | $0 | $0 | View return |
| 2021 | Boothbay Region Education Foundation | 990 | Trustee | 1.5 | $0 | $0 | View return |
| 2020 | Boothbay Region Student Aid Fund Inc. | 990 | Co-President | 1 | $0 | $0 | View return |
| 2020 | Boothbay Region Education Foundation | 990 | Trustee | 1.5 | $0 | $0 | View return |
| 2019 | Koster Insurance Scholarship Fund Inc | 990PF | President,Treasurer,Clerk | 0 | $0 | $0 | View return |
| 2018 | Young Mens Christian Association of Greater Boston Inc. | 990 | Board Member Thru 03/22/2018 | 1 | $0 | $0 | View return |
| 2018 | Koster Insurance Scholarship Fund Inc | 990PF | President,Treasurer,Clerk | 0 | $0 | $0 | View return |
| 2018 | The American College Health Foundation Incorporated | 990 | Director | 1 | $0 | $0 | View return |
| 2017 | Young Mens Christian Association of Greater Boston Inc. | 990 | Board Member | 1 | $0 | $0 | View return |
| 2017 | Koster Insurance Scholarship Fund Inc | 990PF | President,Treasurer,Clerk | 0 | $0 | $0 | View return |
| 2017 | Squashbusters Inc. | 990 | Director | 1 | $0 | $0 | View return |
| 2016 | Koster Insurance Scholarship Fund Inc | 990PF | President,Treasurer,Clerk | 0 | $0 | $0 | View return |
| 2015 | Young Mens Christian Association of Greater Boston Inc. | 990 | Board Member | 1 | $0 | $0 | View return |
| 2015 | Koster Insurance Scholarship Fund Inc | 990PF | President,Treasurer,Clerk | 0 | $0 | $0 | View return |
| 2015 | Squashbusters Inc. | 990 | Director | 1 | $0 | $0 | View return |
| 2015 | The Boston Conservatory | 990 | Trustee | 1 | $0 | $0 | View return |
| 2014 | Koster Insurance Scholarship Fund Inc | 990PF | President,Treasurer,Clerk | 0 | $0 | $0 | View return |
| 2014 | Young Mens Christian Association of Greater Boston Inc. | 990 | Board Member | 1 | - | - | View return |
| 2014 | Squashbusters Inc. | 990 | Director | 1 | $0 | $0 | View return |
| 2014 | The Boston Conservatory | 990 | Trustee | 1 | $0 | $0 | View return |
| 2013 | Young Mens Christian Association of Greater Boston Inc. | 990 | Board Member | 1 | $0 | - | View return |
| 2013 | Koster Insurance Scholarship Fund Inc | 990PF | President,Treasurer,Clerk | 0 | $0 | $0 | View return |
| 2013 | Squashbusters Inc. | 990 | Director | 1 | $0 | $0 | View return |
| 2012 | Koster Insurance Scholarship Fund Inc | 990PF | President,Treasurer,Clerk | 0 | $0 | $0 | View return |
| 2011 | Koster Insurance Scholarship Fund Inc | 990PF | President,Treasurer,Clerk | 0 | $0 | $0 | View return |
| 2010 | Koster Insurance Scholarship Fund Inc | 990PF | President, Treasurer, Cler | 0.5 | $0 | $0 | View return |