The G Harold & Leila Y Mathers Charitable Foundation

Historical Funder

Rye Brook, New York · EIN 23-7441901 · Private foundation · Website

Grants paid (2024)$17.3M

Organizations funded103

Typical grant$225,000

Total assets$392.6M

Half of its grants to organizations were between $30,000 and $241,950.

From the return

How to apply

The foundation filed the following application information (Form 990-PF Part XV, tax year 2024):

Contact	ZACHARY S HANDELMAN DIR-OPERATIONS
Address	800 WESTCHESTER AVENUE STE N-503, RYE BROOK NY 105731373
Phone	9142420465
Form and materials	THERE IS A FORMAL 2 STEP APPLICATION PROCESS THAT MUST BE SUBMITTED THROUGH THE MATHERS FOUNDATION'S ONLINE PORTAL. REFER TO MATHERSFOUNDATION.ORG FOR DETAILS.
Deadlines	GRANT APPLICATIONS ARE REVIEWED ON A TRIMESTER BASIS. REFER TO MATHERSFOUNDATION.ORG FOR DETAILS.
Restrictions	THE FOUNDATION MAKE GRANTS ONLY TO ORGANIZATIONS HAVING TAX EXEMPT STATUS UNDER SECTION 501(C)(3) OF THE INTERNAL REVENUE CODE AND TO THOSE THAT ARE NOT PRIVATE FOUNDATIONS WITHING THE MEANING OF SECTION 509(A), OR IN THE ABSENCE OF SUCH A DETERMINATION, TO A STATE OR ANY POLITICAL SUBDIVISION THEREOF WITHIN THE MEANING OF SEC 170(C)(1), OR A STATE COLLEGE OR UNIVERSITY. THE FOUNDATION DOES NOT MAKE GRANTS TO INDIVIDUALS. THE FOUNDATION RARELY PROVIDES GRANTS FOR PERIODS LONGER THAN THREE YEARS.

Copied as filed. Deadlines on a tax return describe the foundation's usual process; they are not confirmation of a current open cycle.

What it funds

Share of grant lines on the latest return, classified from the purpose each grant states.

Education28
Health18
STEM4
Arts & Culture2
Food Assistance1
Youth Sports1

Where it gives

78% of grants went outside New York.

Grants paid in tax year 2024

Recipient	Location	Purpose	Amount
Rockefeller University	New York, NY	Research project	$277,200
Massachusetts Institute of Technology	Boston, MA	Research project	$270,000
Yale University	New Haven, CT	Research project	$268,534
California Institute of Technology	Pasadena, CA	Research project	$264,398
Leland Stanford Junior University	Stanford, CA	Research project	$259,200
Children's Hospital Corp (Boston Children's Hospital)	Boston, MA	Research project	$256,184
Children's Hospital Corp (Boston Children's Hospital)	Boston, MA	Research project	$253,000
Vanderbilt University Medical Center	Nashville, TN	Research project	$252,199
Case Western Reserve University	Cleveland, OH	Research project	$250,000
Cleveland Clinic Foundation	Cleveland, OH	Research project	$250,000
Cleveland Clinic Foundation	Cleveland, OH	Research project	$250,000
Columbia University	New York, NY	Research project	$250,000
Dana-Farber Cancer Institute	Boston, MA	Research project	$250,000
Dana-Farber Cancer Institute	Boston, MA	Research project	$250,000
President and Fellows of Harvard College	Boston, MA	Research project	$250,000
Rockefeller University	New York, NY	Research project	$250,000
Rockefeller University	New York, NY	Research project	$250,000
The Wistar Institute	Philadelphia, PA	Research project	$250,000
Whitehead Institute for Biomedical Research	Cambridge, MA	Research project	$250,000
White Plains Hospital	White Plains, NY	General purpose	$250,000
University of Michigan	Ann Arbor, MI	Research project	$249,984
Boston College	Chestnut Hill, MA	Research project	$249,935
Icahn School of Medicine at Mt Sinai	New York, NY	Research project	$247,097
Weill Cornell Medical College	New York, NY	Research project	$246,187
Weill Cornell Medical College	New York, NY	Research project	$243,987
Duke University	Durham, NC	Research project	$241,950
Dana-Farber Cancer Institute	Boston, MA	Research project	$240,000
Massachusetts General Hospital	Boston, MA	Research project	$240,000
President and Fellows of Harvard College	Boston, MA	Research project	$240,000
Columbia University	New York, NY	Research project	$238,595
Salk Institute for Biological Studies	LA Jolla, CA	Research project	$234,692
Tufts College	Medford, MA	Research project	$233,522
Dana-Farber Cancer Institute	Boston, MA	Research project	$233,333
Leland Stanford Junior University	Stanford, CA	Research project	$233,333
President and Fellows of Harvard College	Boston, MA	Research project	$233,333
President and Fellows of Harvard College	Boston, MA	Research project	$233,333
University of California Los Angeles	Pasadena, CA	Research project	$233,333
Yale University	New Haven, CT	Research project	$233,333
Cleveland Clinic Foundation	Cleveland, OH	Research project	$233,224
California Institute of Technology	Pasadena, CA	Research project	$233,153
University of California Berkeley	Berkeley, CA	Research project	$233,000
Cuny Advanced Science Research Center	New York, NY	Research project	$231,937
Massachusetts Institute of Technology	Boston, MA	Research project	$230,869
Leland Stanford Junior University	Stanford, CA	Research project	$230,461
Yale University	New Haven, CT	Research project	$228,252
California Institute of Technology	Pasadena, CA	Research project	$227,488
Salk Institute for Biological Studies	LA Jolla, CA	Research project	$227,328
Children's Hospital Corp (Boston Children's Hospital)	Boston, MA	Research project	$225,000
Dana-Farber Cancer Institute	Boston, MA	Research project	$225,000
Dana-Farber Cancer Institute	Boston, MA	Research project	$225,000
Dana-Farber Cancer Institute	Boston, MA	Research project	$225,000
Dana-Farber Cancer Institute	Boston, MA	Research project	$225,000
Vanderbilt University Medical Center	Nashville, TN	Research project	$224,998
Children's Hospital Corp (Boston Children's Hospital)	Boston, MA	Research project	$224,882
Vanderbilt University Medical Center	Nashville, TN	Research project	$223,682
Children's Hospital Corp (Boston Children's Hospital)	Boston, MA	Research project	$220,774
Duke University	Durham, NC	Research project	$218,846
Joslin Diabetes Center	Boston, MA	Research project	$217,051
Memorial Sloan-Kettering Cancer Center	New York, NY	Research project	$215,103
Beth Israel Deaconess Medical Center	New York, NY	Research project	$211,040

Showing the 60 largest of 103 grants to organizations.

Grants approved for future payment

Recipient	Location	Purpose	Amount
Dana-Farber Cancer Institute	Boston, MA	Research project	$1,480,000
Rockefeller University	New York, NY	Research project	$1,000,000
President and Fellows of Harvard College	Boston, MA	Research project	$980,000
Case Western Reserve University	Cleveland, OH	Research project	$500,000
Columbia University	New York, NY	Research project	$500,000
University of Michigan	Ann Arbor, MI	Research project	$499,969
Boston College	Chestnut Hill, MA	Research project	$499,869
Icahn School of Medicine at Mt Sinai	New York, NY	Research project	$494,193
University of California Berkeley	Berkeley, CA	Research project	$493,824
Duke University	Durham, NC	Research project	$483,900
Massachusetts General Hospital	Boston, MA	Research project	$480,000
Tufts College	Medford, MA	Research project	$476,961
Salk Institute for Biological Studies	LA Jolla, CA	Research project	$471,163
Massachusetts Institute of Technology	Boston, MA	Research project	$469,131
Cleveland Clinic Foundation	Cleveland, OH	Research project	$466,448
Weill Cornell Medical College	New York, NY	Research project	$406,013

Giving by year

Tax year	Grants paid	Grant lines
2024	$17,273,778	119
2023	$16,465,249	96

Sources

IRS Form 990-PF, tax year 2024, filed Nov 14, 2025 - IRS e-file batch, object ID 202543189349101854
IRS Tax Exempt Organization Search for EIN 23-7441901
Profile updated Nov 5, 2026

Facts on this page come from the foundation's own IRS Form 990-PF filings as published by the IRS. Grantvello does not know whether a foundation is accepting proposals right now: a past grant is not an open opportunity. Always confirm current guidelines with the funder before applying.