Nonprofit · EIN 46-3770194
PROOF SCHOOL
Tax-exempt · SAN FRANCISCO, CA 94105
Financials
| Year ended | Form | Revenue | Expenses | Net income | Total assets | Liabilities | Net assets |
|---|---|---|---|---|---|---|---|
| June 30, 2025 | 990 | $11,164,213 | $6,650,201 | $4,514,012 | $19,536,521 | $9,071,608 | $10,464,913 |
| June 30, 2024 | 990 | $6,704,431 | $5,936,734 | $767,697 | $11,550,096 | $5,599,195 | $5,950,901 |
| June 30, 2023 | 990 | $6,530,236 | $5,819,619 | $710,617 | $10,068,626 | $4,885,422 | $5,183,204 |
Financial details: 990 for the year ended June 30, 2025
Revenue
- Contributions, gifts and grants
- $4,207,457
- Program service revenue
- $6,597,629
- Investment income
- $353,335
- Net gain from sales of assets
- $18,659
- Other revenue
- $5,792
Expenses
- Grants and similar amounts paid
- $1,200,072
- Compensation of officers, directors and key employees
- $907,665
- Other salaries and wages
- $2,206,230
- Salaries, compensation and benefits (total)
- $3,728,945
- Professional fundraising fees
- $0
- Legal fees
- $2,980
- Accounting fees
- $9,304
- Occupancy
- $949,904
- Depreciation
- $281,869
- Program services (functional)
- $6,112,438
- Management and general (functional)
- $519,864
- Fundraising (functional)
- $17,899
Balance sheet and other
- Total assets, start of year
- $11,550,096
- Total assets, end of year
- $19,536,521
- Total liabilities, end of year
- $9,071,608
- Net assets, end of year
- $10,464,913
- Land, buildings and equipment
- $3,305,005
- Publicly traded securities
- $8,728,370
- Gross receipts
- $12,823,279
- Employees
- 31
- Volunteers
- 8
- Year formed
- 2013
- State of legal domicile
- CA
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 for the year ended June 30, 2025, highest compensation first.
| Name | Title | Hours / week | Compensation | Other / benefits |
|---|---|---|---|---|
| SAMUEL VANDERVELDE | HEAD OF SCHOOL Trustee or director, Officer | 40 | $267,945 | $25,347 |
| ZACHARY SIFUENTES | DEAN OF HUMANITIES Key employee | 40 | $242,597 | $19,278 |
| KATHY LIN | DIRECTOR OF ADMISSIONS Key employee | 40 | $253,120 | $873 |
| JASON HOROWITZ | MATH & SCIENCE TEACHER Highest-paid employee | 40 | $124,168 | $12,757 |
| ILYSE GORDIS | LANGUAGE ARTS & HISTORY TEACHER Highest-paid employee | 40 | $110,781 | $25,843 |
| SUSAN DURST | MATH & MUSIC TEACHER Highest-paid employee | 40 | $122,671 | $8,083 |
| MICHAEL YETMAN | DIR OF SCIENCE CURRICULAR & PROGRAMS Highest-paid employee | 40 | $111,605 | $17,467 |
| CONNIE YOU | LITERATURE TEACHER Highest-paid employee | 40 | $114,657 | $11,154 |
| PAUL ZEITZ | BOARD CHAIR Trustee or director, Officer | 2 | $0 | $0 |
| PERRY TAM | TREASURER Trustee or director, Officer | 0.5 | $0 | $0 |
| ALON AMIT | SECRETARY Trustee or director, Officer | 0.5 | $0 | $0 |
| JAMES SOTIROS | BOARD OF DIRECTORS Trustee or director | 0.5 | $0 | $0 |
| RAVI VAKIL | BOARD OF DIRECTORS Trustee or director | 0.5 | $0 | $0 |
| LISA PARK | BOARD OF DIRECTORS Trustee or director | 0.5 | $0 | $0 |
| SUSAN ATHEY | BOARD OF DIRECTORS Trustee or director | 0.5 | $0 | $0 |
1 more people on this return
| Name | Title | Hours / week | Compensation |
|---|---|---|---|
| CAROLINE JONES | BOARD OF DIRECTORS Trustee or director | 0.5 | $0 |
990 for the year ended June 30, 2024: 14 people
| Name | Title | Hours / week | Compensation | Other / benefits |
|---|---|---|---|---|
| SAMUEL VANDERVELDE | HEAD OF SCHOOL Trustee or director, Officer | 40 | $250,853 | $22,359 |
| ZACHARY SIFUENTES | DEAN OF HUMANITIES Key employee | 40 | $223,153 | $16,993 |
| KATHY LIN | DIRECTOR OF ADMISSIONS Key employee | 40 | $234,360 | $873 |
| JASON HOROWITZ | MATH & SCIENCE TEACHER Highest-paid employee | 40 | $114,878 | $11,105 |
| ILYSE GORDIS | LANGUAGE ARTS & HISTORY TEACHER Highest-paid employee | 40 | $100,213 | $22,522 |
| SUSAN DURST | MATH & MUSIC TEACHER Highest-paid employee | 40 | $111,833 | $7,316 |
| CONNIE YOU | LITERATURE TEACHER Highest-paid employee | 40 | $100,470 | $9,736 |
| PAUL ZEITZ | BOARD CHAIR Trustee or director, Officer | 2 | $0 | $0 |
| PERRY TAM | TREASURER Trustee or director, Officer | 0.5 | $0 | $0 |
| ALON AMIT | SECRETARY Trustee or director, Officer | 0.5 | $0 | $0 |
| JAMES SOTIROS | BOARD OF DIRECTORS Trustee or director | 0.5 | $0 | $0 |
| RAVI VAKIL | BOARD OF DIRECTORS Trustee or director | 0.5 | $0 | $0 |
| LISA PARK | BOARD OF DIRECTORS Trustee or director | 0.5 | $0 | $0 |
| SUSAN ATHEY | BOARD OF DIRECTORS Trustee or director | 0.5 | $0 | $0 |
990 for the year ended June 30, 2023: 14 people
| Name | Title | Hours / week | Compensation | Other / benefits |
|---|---|---|---|---|
| SAMUEL VANDERVELDE | HEAD OF SCHOOL Trustee or director, Officer | 40 | $244,080 | $43,660 |
| ZACHARY SIFUENTES | DEAN OF HUMANITIES Key employee | 40 | $210,489 | $36,264 |
| KATHY LIN | DIRECTOR OF ADMISSIONS Key employee | 40 | $219,974 | $11,926 |
| JASON HOROWITZ | MATH & SCIENCE TEACHER Highest-paid employee | 40 | $106,245 | $17,210 |
| SUSAN DURST | MATH & MUSIC TEACHER Highest-paid employee | 40 | $103,917 | $13,795 |
| PAUL ZEITZ | BOARD CHAIR Trustee or director, Officer | 2 | $0 | $0 |
| PERRY TAM | TREASURER Trustee or director | 0.5 | $0 | $0 |
| ALON AMIT | SECRETARY Trustee or director | 0.5 | $0 | $0 |
| DIVIYA MAGARO | BOARD MEMBER Trustee or director | 0.5 | $0 | $0 |
| JAMES SOTIROS | BOARD MEMBER Trustee or director | 0.5 | $0 | $0 |
| RAVI VAKIL | BOARD MEMBER Trustee or director | 0.5 | $0 | $0 |
| ANA BRUBAKER | BOARD MEMBER Trustee or director | 0.5 | $0 | $0 |
| LISA PARK | BOARD MEMBER Trustee or director | 0.5 | $0 | $0 |
| SUSAN ATHEY | BOARD MEMBER Trustee or director | 0.5 | $0 | $0 |
Address and contacts
- Address (IRS master file)
- 221 MAIN ST SUITE 104, SAN FRANCISCO, CA 94105-1906
- In care of
- % ZACHARY SIFUENTES
- Principal officer (990 for 2024)
- SAMUEL VANDERVELDE, 221 MAIN STREET 104, SAN FRANCISCO, CA 94105
- Signed the 990
- SAMUEL VANDERVELDE, HEAD OF SCHOOL
- Phone
- (415) 930-0182
- Website
- WWW.PROOFSCHOOL.ORG
- Return prepared by
- HOOD & STRONG LLP
California records
California keeps its own records of charities and corporations. Search them by EIN 46-3770194 or by the name PROOF SCHOOL.
- Attorney General, Registry of Charities and Fundraisers
- Registration status and filed reports (CT-TR-1, RRF-1)
- Secretary of State, bizfile Online
- Corporation status, entity number, agent for service
- Franchise Tax Board
- Entity status letter (state tax exemption, good standing)
Mission
PROOF SCHOOL OFFERS A TRANSFORMATIVE LIBERAL ARTS EDUCATION TO YOUNG PEOPLE WITH AN ACTIVE CURIOSITY AND A PASSION FOR MATHEMATICS, EQUIPPING THEM TO REASON, COMMUNICATE, AND POSITIVELY IMPACT THEIR WORLD.
Program accomplishments
- PROOF SCHOOL DELIVERED A COMPREHENSIVE MIDDLE AND HIGH SCHOOL CURRICULUM TO A TOTAL OF 125 STUDENTS IN GRADES 6-12 DURING THE 2024-25 ACADEMIC YEAR. SCHOOL WAS IN SESSION FOR 171 DAYS; THE SCHOOL HELD INFO SESSIONS, RAN ADMISSIONS, AND GRADUATED 15 STUDENTS. THE GOAL FOR THE SCHOOL CONTINUES TO BE TO PROVIDE A WORLD CLASS EDUCATION FOR STUDENTS IN THE BAY AREA WHO LOVE MATH.Expenses $6,112,438 · grants $1,200,072 · revenue $6,603,421
What it must file and when
IRS records say it files Form 990 or 990-EZ. Based on its last return; a smaller organization may file the 990-N. Its accounting year ends in June, so each return is due on the 15th day of the 5th month after that.
| Tax year | Year ended | Due | IRS public records |
|---|---|---|---|
| 2025 | June 30, 2026 | November 16, 2026 | Not due yet |
| 2024 | June 30, 2025 | November 17, 2025 | 990 on file |
| 2023 | June 30, 2024 | November 15, 2024 | 990 on file |
IRS record
- EIN
- 46-3770194
- Tax-exempt status
- 501(c)(3): Charitable, religious, educational or scientific organization
- Foundation status
- School
- Donations deductible (Pub 78)
- Public charity, 50% deduction limit
- Exempt since
- 2014
- Accounting year ends
- June
- Files
- Form 990 or 990-EZ
- Category (NTEE)
- Education (B25)
- Assets (IRS master file)
- $19,536,521
- Income (IRS master file)
- $12,823,279
Filing history
| Form | Year ended | Revenue | Expenses | Assets | Return |
|---|---|---|---|---|---|
| 990 | June 2025 | $11,164,213 | $6,650,201 | $19,536,521 | IRS |
| 990 | June 2024 | $6,704,431 | $5,936,734 | $11,550,096 | IRS |
| 990 | June 2023 | $6,530,236 | $5,819,619 | $10,068,626 | XML |
| 990 | June 2022 | $6,376,046 | $5,884,439 | $9,200,704 | IRS |
| 990 | June 2021 | – | – | – | IRS |
| 990 | June 2020 | – | – | – | IRS |
| 990 | June 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 46-3770194).
Questions about PROOF SCHOOL
- What is the EIN of PROOF SCHOOL?
- The employer identification number (EIN) of PROOF SCHOOL is 46-3770194.
- Is PROOF SCHOOL tax-exempt?
- Yes. The IRS lists it as tax-exempt under section 501(c)(3) since 2014.
- Are donations to PROOF SCHOOL tax-deductible?
- Yes. It is listed in IRS Publication 78 (Public charity, 50% deduction limit).
- Which annual return does PROOF SCHOOL file?
- Form 990 or 990-EZ. Based on its last return; a smaller organization may file the 990-N.
- When is the next return of PROOF SCHOOL due?
- The return for tax year 2025 (the year ending June 30, 2026) is due November 16, 2026. Form 8868 extends it by six months; the 990-N cannot be extended.
- When did PROOF SCHOOL last file with the IRS?
- The latest return in the IRS public files is the 990 for the year ended June 2025.
- Who is the principal officer of PROOF SCHOOL?
- The 990 for the year ended June 30, 2025 names SAMUEL VANDERVELDE.
- Who are the officers and directors of PROOF SCHOOL?
- The 990 for the year ended June 30, 2025 lists 16 people; 8 received compensation from the organization, the highest $267,945 (SAMUEL VANDERVELDE, HEAD OF SCHOOL).
- How much revenue does PROOF SCHOOL have?
- On its 990 for the year ended June 30, 2025 it reported revenue of $11,164,213, expenses of $6,650,201 and total assets of $19,536,521 at year end.
Other nonprofits in SAN FRANCISCO
- UNIVERSITY OF CALIFORNIA SAN FRANCISCO FOUNDATION EIN 94-2829914 · last filed 990 for 2025
- UNIVERSITY OF SAN FRANCISCO EIN 94-1156628 · last filed 990 for 2025
- SHINE BC-LA EIN 84-3947799 · last filed 990 for 2025
- WIKIMEDIA FOUNDATION ORG EIN 20-0049703 · last filed 990 for 2025
- KIPP FOUNDATION EIN 94-3362724 · last filed 990 for 2025
- CALIFORNIA COLLEGE OF THE ARTS EIN 94-1156485 · last filed 990 for 2025
- FIVE KEYS SCHOOLS AND PROGRAMS EIN 81-0622701 · last filed 990 for 2025
- BRILLIANT CORNERS EIN 56-2379862 · last filed 990 for 2025