Nonprofit · EIN 82-3801384
WILLIAM AND SUSAN MATHESON FOUNDATION INC
Tax-exempt · DE PERE, WI 54115
Financials
| Year ended | Form | Revenue | Expenses | Net income | Total assets | Liabilities | Net assets |
|---|---|---|---|---|---|---|---|
| December 31, 2025 | 990-PF | $990,571 | $248,068 | $742,503 | $4,057,970 | $0 | $4,057,970 |
| December 31, 2024 | 990-PF | $220,939 | $191,497 | $29,442 | $3,671,267 | $39,600 | $3,631,667 |
| December 31, 2023 | 990-PF | $91,087 | $169,253 | -$78,166 | $3,602,225 | $0 | $3,602,225 |
Financial details: 990-PF for the year ended December 31, 2025
Revenue
- Contributions, gifts and grants
- $491,597
- Dividends
- $59,695
- Net gain from sales of assets
- $439,279
Expenses
- Grants and similar amounts paid
- $228,900
- Compensation of officers, directors and key employees
- $0
- Disbursements for charitable purposes
- $229,385
- Excise tax on investment income
- $6,676
Balance sheet and other
- Total assets, start of year
- $3,671,267
- Total assets, end of year
- $4,057,970
- Total liabilities, end of year
- $0
- Net assets, end of year
- $4,057,970
- Fair market value of assets
- $4,741,681
- Qualifying distributions
- $229,385
- Net investment income
- $498,974
From the e-filed returns the IRS publishes as XML (latest three processing years; amended returns replace the original). PDF copies at the IRS.
Officers, directors and key employees
As listed on the 990-PF for the year ended December 31, 2025, highest compensation first.
| Name | Title | Hours / week | Compensation |
|---|---|---|---|
| WILLIAM J MATHESON 2118 RIDGE HAVEN CT, DE PERE, WI 54115 | PRESIDENT; TREASURER; DIRE | 1 | $0 |
| SUSAN M MATHESON 2118 RIDGE HAVEN CT, DE PERE, WI 54115 | VICE PRES; SECRETARY; DIRE | 1 | $0 |
| EMILY E MARINOFF 2118 RIDGE HAVEN CT, DE PERE, WI 54115 | DIRECTOR | 0.5 | $0 |
| JOSEPH W MATHESON 2118 RIDGE HAVEN CT, DE PERE, WI 54115 | DIRECTOR | 0.5 | $0 |
| AMY MATHESON 2118 RIDGE HAVEN CT, DE PERE, WI 54115 | DIRECTOR | 0.5 | $0 |
990-PF for the year ended December 31, 2024: 5 people
| Name | Title | Hours / week | Compensation |
|---|---|---|---|
| WILLIAM J MATHESON 2118 RIDGE HAVEN CT, DE PERE, WI 54115 | PRESIDENT; TREASURER; DIRE | 1 | $0 |
| SUSAN M MATHESON 2118 RIDGE HAVEN CT, DE PERE, WI 54115 | VICE PRES; SECRETARY; DIRE | 1 | $0 |
| EMILY E MARINOFF 2118 RIDGE HAVEN CT, DE PERE, WI 54115 | DIRECTOR | 0.5 | $0 |
| JOSEPH W MATHESON 2118 RIDGE HAVEN CT, DE PERE, WI 54115 | DIRECTOR | 0.5 | $0 |
| AMY MATHESON 2118 RIDGE HAVEN CT, DE PERE, WI 54115 | DIRECTOR | 0.5 | $0 |
990-PF for the year ended December 31, 2023: 5 people
| Name | Title | Hours / week | Compensation |
|---|---|---|---|
| WILLIAM J MATHESON 2118 RIDGE HAVEN CT, DE PERE, WI 54115 | PRESIDENT; TREASURER; DIRE | 1 | $0 |
| SUSAN M MATHESON 2118 RIDGE HAVEN CT, DE PERE, WI 54115 | VICE PRES; SECRETARY; DIRE | 1 | $0 |
| EMILY E MARINOFF 2118 RIDGE HAVEN CT, DE PERE, WI 54115 | DIRECTOR | 0.5 | $0 |
| JOSEPH W MATHESON 2118 RIDGE HAVEN CT, DE PERE, WI 54115 | DIRECTOR | 0.5 | $0 |
| AMY MATHESON 2118 RIDGE HAVEN CT, DE PERE, WI 54115 | DIRECTOR | 0.5 | $0 |
Address and contacts
- Address (IRS master file)
- 2118 RIDGE HAVEN CT, DE PERE, WI 54115-7982
- Signed the 990-PF
- WILLIAM MATHESON, PRESIDENT
- Phone
- (920) 632-4112
- Return prepared by
- HAWKINS ASH CPAS LLP
What it must file and when
IRS records say it files Form 990-PF. Private foundations file every year. Its accounting year ends in December, so each return is due on the 15th day of the 5th month after that.
| Tax year | Year ended | Due | IRS public records |
|---|---|---|---|
| 2025 | December 31, 2025 | May 15, 2026 | 990-PF on file |
| 2024 | December 31, 2024 | May 15, 2025 | 990-PF on file |
| 2023 | December 31, 2023 | May 15, 2024 | 990-PF on file |
IRS record
- EIN
- 82-3801384
- Tax-exempt status
- 501(c)(3): Charitable, religious, educational or scientific organization
- Foundation status
- Private non-operating foundation
- Donations deductible (Pub 78)
- Private foundation, 30% limit
- Exempt since
- 2018
- Accounting year ends
- December
- Files
- Form 990-PF
- Category (NTEE)
- Philanthropy, voluntarism and grantmaking foundations (T20)
- Assets (IRS master file)
- $4,057,970
- Income (IRS master file)
- $2,561,880
Filing history
| Form | Year ended | Revenue | Expenses | Assets | Return |
|---|---|---|---|---|---|
| 990-PF | December 2025 | $990,571 | $248,068 | $4,057,970 | XML |
| 990-PF | December 2024 | $220,939 | $191,497 | $3,671,267 | IRS |
| 990-PF | December 2023 | $91,087 | $169,253 | $3,602,225 | XML |
| 990-PF | December 2022 | – | – | – | IRS |
| 990-PF | December 2021 | – | – | – | IRS |
| 990-PF | December 2020 | – | – | – | IRS |
| 990-PF | December 2018 | – | – | – | IRS |
990-N: the IRS bulk file holds only the latest e-Postcard per organization; earlier years come from archived copies of that file since 2020 and can have gaps (the IRS e-Postcard search lists every one). 990, 990-EZ, 990-PF, 990-T: every e-filed return in the IRS e-file index since 2019; XML for the latest three processing years, amounts from the IRS Statistics of Income extracts before that. PDF copies and determination letters at the IRS (search EIN 82-3801384).
Questions about WILLIAM AND SUSAN MATHESON FOUNDATION INC
- What is the EIN of WILLIAM AND SUSAN MATHESON FOUNDATION INC?
- The employer identification number (EIN) of WILLIAM AND SUSAN MATHESON FOUNDATION INC is 82-3801384.
- Is WILLIAM AND SUSAN MATHESON FOUNDATION INC tax-exempt?
- Yes. The IRS lists it as tax-exempt under section 501(c)(3) since 2018.
- Are donations to WILLIAM AND SUSAN MATHESON FOUNDATION INC tax-deductible?
- Yes. It is listed in IRS Publication 78 (Private foundation, 30% limit).
- Which annual return does WILLIAM AND SUSAN MATHESON FOUNDATION INC file?
- Form 990-PF. Private foundations file every year.
- When is the next return of WILLIAM AND SUSAN MATHESON FOUNDATION INC due?
- The return for tax year 2026 (the year ending December 31, 2026) is due May 17, 2027. Form 8868 extends it by six months; the 990-N cannot be extended.
- When did WILLIAM AND SUSAN MATHESON FOUNDATION INC last file with the IRS?
- The latest return in the IRS public files is the 990-PF for the year ended December 2025.
- Who are the officers and directors of WILLIAM AND SUSAN MATHESON FOUNDATION INC?
- The 990-PF for the year ended December 31, 2025 lists 5 people; 0 received compensation from the organization.
- How much revenue does WILLIAM AND SUSAN MATHESON FOUNDATION INC have?
- On its 990-PF for the year ended December 31, 2025 it reported revenue of $990,571, expenses of $248,068 and total assets of $4,057,970 at year end.
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