Skip to content
Nonprofiteer
← All organizations

SLATE SCHOOL INC

EIN 81-5374114 NORTH HAVEN, CT

Browse the largest nonprofits in Connecticut

Revenue 2023
$10,953,370
Expenses 2023
$1,814,555

Program services were 94.4% of total expenses calculated — Part IX's program-services column over total expenses, both as filed.

As filed

Subsection
03
NTEE code
B20
Classification
1200
Street
124 MANSFIELD RD

These codes are the IRS's own and are shown exactly as filed. What each one means is in the Business Master File documentation (opens in a new tab).

Other organizations at this address

1 other organization in the IRS Business Master File lists the same street address. matched by us

We match the street line and ZIP code as the IRS gives them, ignoring case and outer spaces and nothing else, so "AVE" and "AVENUE" count as different streets and this list can miss some. A shared address can mean related organizations or a shared office, but it can also be a registered agent, a mail drop or a service provider holding mail for unrelated clients. It is not, by itself, evidence that two organizations are connected.

Mission and programs · 2023

Mission

THE SLATE SCHOOL, INC. IS DESIGNED TO CULTIVATE STUDENT CREATIVITY, FOSTER INGENUITY, AND INSPIRE A DEEP PASSION FOR LIFELONG LEARNING AND DISCOVERY. THE ORGANIZATIONS MISSION AND PRIORITY IS THAT EACH CHILD'S INNATE AND NATURAL LOVE FOR LEARNING BE NURTURED AND ENABLED TO GROW AND FLOURISH.

Activities or mission (Part I)

AT SLATE SCHOOL, INC., EDUCATION IS FOCUSED ON CULTIVATING CREATIVITY, FOSTERING INGENUITY, AND INSPIRING A DEEP PASSION FOR LIFELONG LEARNING. THE ORGANIZATION IS COMMITTED TO CHANGING THE LANDSCAPE OF EDUCATION TO INSPIRE AND NURTURE CHILDREN AS CREATIVE THINKERS AND CURIOUS LEARNERS.

  • K-12 ELEMENTARY SCHOOL

    Expenses $1,712,493

  • UPPER SCHOOL DEVELOPMENT AND CONSTRUCTION. DURING THE FISCAL YEAR $15,468,978 OF COSTS RELATING TO SLATE UPPER SCHOOL WERE EXPENDED AND CAPITALIZED AS CONSTRUCTION IN PROCESS.

As filed on the 2023 return. The filer continues this part on Schedule O, which is not shown here.

Officers and directors · 2023

As listed in Part VII of the 2023 return, in the order the filer printed them. Each return names its own; this is not a roster the organization keeps with us.

  • Alexander Clark

    TREASURER/SECRETARY

    Total calculated
    $0
    Hours/week
    1
  • Jennifer Staple-Clark

    PRESIDENT

    Total calculated
    $0
    Hours/week
    50
  • Paul Ellingstad

    DIRECTOR

    Total calculated
    $0
    Hours/week
    1
  • Julie Mountcastle

    HEAD OF SCHOOL

    Total calculated
    $156,109
    From this org
    $151,032
    From related orgs
    $0
    Other
    $5,077
    Hours/week
    60

    Schedule J breakdown matched by us

    Base
    $151,032
    Bonus
    $0
    Other
    $0
    Deferred
    $5,077
    Nontaxable benefits
    $0
    Filer's total
    $156,109
  • Wendy Ostroff

    DIRECTOR

    Total calculated
    $0
    Hours/week
    1

Compensation is as filed in Part VII: reportable pay from this organization and from related organizations, other compensation, and hours per week. The total, marked calculated, is our sum of the three dollar columns, with a blank column counted as $0; the form itself has no total. On a Form 990-EZ the columns are Part IV's instead, and on a Form 990-PF Part VIII's — compensation, contributions to benefit plans, and expense account — and the total sums those. A Schedule J breakdown is as filed: base pay, bonus, other, deferred compensation and nontaxable benefits from this organization, with any from related organizations beside each, and the filer's own total. It is shown with the Part VII listing of the same name on the same return. The form gives no key between the two, so that pairing is ours, and is marked matched by us. Earlier years are each on their own filing page.

Filings

  • 2023
    Revenue
    $10,953,370
    Expenses
    $1,814,555
    Contributions
    $10,125,709
    Grants paid
    $0
  • 2022
    Revenue
    $11,643,767
    Expenses
    $1,437,729
    Contributions
    $11,003,340
    Grants paid
    $0

The four totals the IRS asks for on Part I of the Form 990, as filed. A dash means the figure was not present on the return — not that it was zero.

Other returns filed

  • 2021 · 990

    Revenue
    $4,188,602
    Expenses
    $1,366,652
    Assets (EOY)
    $18,120,974
  • 2020 · 990

    Revenue
    $1,399,409
    Expenses
    $1,196,623
    Assets (EOY)
    $15,230,951
  • 2019 · 990

    Revenue
    $7,054,688
    Expenses
    $1,350,933
    Assets (EOY)
    $15,004,081
  • 2019 · 990

    Revenue
    $7,054,688
    Expenses
    $1,350,933
    Assets (EOY)
    $15,004,081
  • 2018 · 990

    Revenue
    $6,989,658
    Expenses
    $914,757
    Assets (EOY)
    $13,203,934
  • 2017 · 990

    Revenue
    $3,236,399
    Expenses
    $187,720
    Assets (EOY)
    $9,206,702

Nonprofiteer parses Forms 990, 990-EZ and 990-PF, in a window of recent tax years. These returns are recorded from the IRS e-file index, so their figures were extracted by that index rather than read from the return here — treat them as a different source from the filings above, not as more of the same record. A dash means the index carries no figure; Form 990-T listings carry none at all.

Grants made

No itemized grants to organizations. Schedule I is filed only by organizations that granted more than $5,000 to a recipient, so most filers have none.

Grants received

Other IRS files

Auto-Revocation List

Not listed. The IRS publishes this list for organizations whose exemption was automatically revoked for failing to file for three consecutive years.

Publication 78

Listed as of 13 October 2026, under deductibility PC.

These are two separate IRS files on two separate schedules, shown as published and not reconciled with each other. Neither is a statement about whether a contribution is deductible today: 19,245 organizations appear in Publication 78 while the IRS's own revocation file lists them as currently revoked, more than half of those revoked before 2019. Absence from Publication 78 is evidence of nothing, and presence is not evidence either. Verify current status with the IRS before relying on it.

What this page reflects

The registration facts above come from the IRS Business Master File published 13 October 2026 and read 1 November 2026, for every organization at once. Returns through tax year 2023, the newest we have parsed for this organization.