| 2025 | Paul Koster Memorial Benefit Inc | 990EZ | President | 1 | $0 | - | View return |
| 2025 | North Sea Community Schoolhouse Association Inc. | 990EZ | President | 1 | $0 | - | View return |
| 2024 | International Research and Exchanges Board Inc. | 990 | Chief Of Party (To Mar '25) | 40 | $216,684 | $0 | View return |
| 2024 | International Research and Exchanges Board Inc. | 990 | Chief Of Party (To Mar '25) | 40 | $216,684 | $0 | View return |
| 2024 | Rachel Kohl Community Library Inc | 990 | See Schedule | 1 | $0 | $0 | View return |
| 2024 | Paul Koster Memorial Benefit Inc | 990EZ | President | 1 | $0 | - | View return |
| 2023 | International Research and Exchanges Board Inc. | 990 | Chief Of Party | 40 | $207,061 | $0 | View return |
| 2023 | Paul Koster Memorial Benefit Inc | 990EZ | President | 0 | $0 | - | View return |
| 2023 | Rachel Kohl Community Library Inc | 990 | President | 1 | $0 | $0 | View return |
| 2022 | International Research and Exchanges Board Inc. | 990 | Chief Of Party, Sri Lanka | 40 | $194,499 | $0 | View return |
| 2022 | Paul Koster Memorial Benefit Inc | 990EZ | President | 1 | $0 | - | View return |
| 2022 | Rachel Kohl Community Library Inc | 990 | President | 1 | $0 | $0 | View return |
| 2021 | International Research and Exchanges Board Inc. | 990 | Chief Of Party, Sri Lanka Media Empowerment For A | 40 | $183,997 | $0 | View return |
| 2021 | Paul Koster Memorial Benefit Inc | 990EZ | President | 1 | $0 | - | View return |
| 2021 | Rachel Kohl Community Library Inc | 990 | President | 0 | $0 | $0 | View return |
| 2020 | International Research and Exchanges Board Inc. | 990 | Chief Of Party, Sri Lanka | 40 | $164,099 | $0 | View return |
| 2020 | Rachel Kohl Community Library Inc | 990 | President | 0 | $0 | $0 | View return |
| 2020 | Paul Koster Memorial Benefit Inc | 990EZ | President | 1 | $0 | - | View return |
| 2020 | Waltham Municipal Employees Credit Union | 990EZ | Director | 0 | $0 | $0 | View return |
| 2019 | Waltham Municipal Employees Credit Union | 990 | Director | - | $0 | $0 | View return |
| 2019 | Rachel Kohl Community Library Inc | 990 | Secretary | 0 | $0 | $0 | View return |
| 2019 | Paul Koster Memorial Benefit Inc | 990EZ | President | 1 | $0 | - | View return |
| 2018 | Waltham Municipal Employees Credit Union | 990 | Director | - | $0 | $0 | View return |
| 2018 | Paul Koster Memorial Benefit Inc | 990EZ | President | 1 | $0 | - | View return |
| 2018 | Rachel Kohl Community Library Inc | 990 | Secretary | 0 | $0 | $0 | View return |
| 2018 | Waltham Municipal Employees Credit Union | 990 | Director | - | $0 | $0 | View return |
| 2018 | Paul Koster Memorial Benefit Inc | 990EZ | President | 1 | $0 | - | View return |
| 2017 | Paul Koster Memorial Benefit Inc | 990EZ | President | 1 | $0 | - | View return |
| 2017 | Rachel Kohl Community Library Inc | 990 | Secretary | 0 | $0 | $0 | View return |
| 2017 | Waltham Municipal Employees Credit Union | 990 | Director | - | $0 | $0 | View return |
| 2016 | Rachel Kohl Community Library Inc | 990 | Secretary | 0 | $0 | $0 | View return |
| 2016 | Paul Koster Memorial Benefit Inc | 990EZ | President | 1 | $0 | - | View return |
| 2015 | Paul Koster Memorial Benefit Inc | 990EZ | President | 0 | $0 | - | View return |
| 2015 | Rachel Kohl Community Library Inc | 990 | Secretary | 0 | $0 | $0 | View return |
| 2014 | Paul Koster Memorial Benefit Inc | 990EZ | President | 0 | $0 | - | View return |
| 2014 | Alanno Society of Rapid City Inc | 990EZ | Board Member | 1 | $0 | $0 | View return |
| 2013 | Paul Koster Memorial Benefit Inc | 990EZ | President | 1 | $0 | - | View return |