Foundation directory

Foundations starting with O

160 private foundations with profiled giving history. Figures from IRS 990-PF filings.

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Typical grant is the median of grants reported in the filing data.

1–24 of 160 foundations in this list

O'Donnell Foundation

Latest IRS filing: 2025 · Current application dates need confirmation.

Most reported giving: TX, VA

Typical grant
$1M
Total giving
$218.8M
Grants reported
43
Open Society Institute

Latest IRS filing: 2024 · Current application dates need confirmation.

Most reported giving: NY, DC, CA

Typical grant
$15K
Total giving
$146.9M
Grants reported
559
Otto Bremer Trust

Latest IRS filing: 2025 · Current application dates need confirmation.

Most reported giving: MN, WI, ND

Typical grant
$55K
Total giving
$125.8M
Grants reported
1,063
One8 Foundation

Latest IRS filing: 2024 · Current application dates need confirmation.

Most reported giving: MA, NY, CA

Typical grant
$50K
Total giving
$48.8M
Grants reported
188
Omidyar Network Fund Inc

Latest IRS filing: 2024 · Current application dates need confirmation.

Most reported giving: DC, NY, CA

Typical grant
$100K
Total giving
$38.1M
Grants reported
242
Oberndorf Family Foundation

Latest IRS filing: 2025 · Current application dates need confirmation.

Most reported giving: CA, TX, OH

Typical grant
$25K
Total giving
$36M
Grants reported
112
Orland Bethel Family Foundation

Latest IRS filing: 2025 · Current application dates need confirmation.

Most reported giving: PA, NY, MA

Typical grant
$7.5K
Total giving
$27.8M
Grants reported
10
Osteopathic Heritage Foundation

Latest IRS filing: 2025 · Current application dates need confirmation.

Most reported giving: OH, MD, IL

Typical grant
$47.5K
Total giving
$24.5M
Grants reported
129
The Oprah Winfrey Charitable Foundation

Latest IRS filing: 2024 · Current application dates need confirmation.

Most reported giving: CA, IL, MD

Typical grant
$150K
Total giving
$23.4M
Grants reported
25
Open Doors International Inc

Latest IRS filing: 2024 · Current application dates need confirmation.

Most reported giving: JOHANNESBURG, HARDERWIJK, QUEZON CITY

Typical grant
$611.7K
Total giving
$22.6M
Grants reported
9
Oneroot Foundation

Latest IRS filing: 2025 · Current application dates need confirmation.

Most reported giving: CA, CO, NY

Typical grant
$25K
Total giving
$15.1M
Grants reported
104
The Otis Booth Foundation

Latest IRS filing: 2023 · Current application dates need confirmation.

Most reported giving: CA, NY, ID

Typical grant
$25K
Total giving
$14.4M
Grants reported
140
Once Upon A Time Foundation

Latest IRS filing: 2024 · Current application dates need confirmation.

Most reported giving: TX, NC, DC

Typical grant
$350
Total giving
$10.7M
Grants reported
1,039
Onesight Essilorluxottica Foundation Fund

Latest IRS filing: 2024 · Current application dates need confirmation.

Most reported giving: GASABO, KIGALI CI, CHENNAI, JOHANNESBURG

Typical grant
$27.7K
Total giving
$10.3M
Grants reported
79
Offutt Family Foundation

Latest IRS filing: 2024 · Current application dates need confirmation.

Most reported giving: MN, ND, NY

Typical grant
$5K
Total giving
$9.6M
Grants reported
114
October Mountain Foundation Inc

Latest IRS filing: 2025 · Current application dates need confirmation.

Most reported giving: NY, MI, MA

Typical grant
$30K
Total giving
$9.4M
Grants reported
141
O'Neill Family Charitable Trust

Latest IRS filing: 2024 · Current application dates need confirmation.

Most reported giving: NY, VA, MA

Typical grant
$20K
Total giving
$8.5M
Grants reported
149
The Overbrook Foundation

Latest IRS filing: 2024 · Current application dates need confirmation.

Most reported giving: NY, DC, CA

Typical grant
$47.5K
Total giving
$8.3M
Grants reported
160
The Oak Hill Fund

Latest IRS filing: 2025 · Current application dates need confirmation.

Most reported giving: VA, CO, FL

Typical grant
$25K
Total giving
$8M
Grants reported
206
Otto Schoitz Foundation

Latest IRS filing: 2024 · Current application dates need confirmation.

Most reported giving: IA, MA

Typical grant
$25K
Total giving
$7.2M
Grants reported
108
Oakwood Foundation Charitable Trust

Latest IRS filing: 2024 · Current application dates need confirmation.

Most reported giving: VA, NC, DC

Typical grant
$10K
Total giving
$6.9M
Grants reported
46

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