Additional Ventures Foundation

Additional Ventures Foundation is one of the most narrowly focused major health research funders in the United States. Every dollar it awards targets a single condition: single ventricle (SV) heart disease — a group of congenital cardiac defects including hypoplastic left heart syndrome, tricuspid atresia, and pulmonary atresia with intact ventricular septum. If your research does not directly address outcomes for people living with SV defects, you are not eligible regardless of scientific merit.

The foundation was established in 2017 by Erin Hoffmann (President and Chairman) and Michael Schroepfer (CFO, former CTO of Meta/Facebook), whose family has a personal connection to the condition. Both serve without compensation, and the organization reflects Silicon Valley's technology-accelerationist culture: it favors bold, high-risk ideas, values rapid iteration, and explicitly recruits researchers from adjacent fields who bring new methodologies to SV science.

The relationship progression depends on which program you pursue. The flagship Single Ventricle Research Fund (SVRF) requires a Letter of Intent (LOI) submitted through ProposalCentral; only invited applicants may submit a full proposal. Turnaround from LOI to award announcement spans roughly nine months. The Expansion Award ($50,000, one year) does not require an LOI and is explicitly designed for researchers new to the SV space — making it the recommended entry point for first-time applicants. The Catalyst to Independence Award targets postdoctoral researchers and early-career investigators, while the Translational Accelerator / Device Innovation Award is milestone-driven and open to companies as well as academic institutions.

First-time applicants should: (1) attend the annual Single Ventricle Investigator Meeting (SVIM) to establish relationships with funded investigators and program staff before applying; (2) start with the Expansion Award rather than the SVRF to demonstrate SV relevance; and (3) demonstrate familiarity with the existing funded research portfolio — grantees at Boston Children's Hospital ($3.15M across 9 grants), Stanford University ($2.04M across 12 grants), and Nationwide Children's Hospital are the organization's most frequent partners and can serve as collaborators or references.

Additional Ventures' annual giving has fluctuated significantly, reflecting the multi-year disbursement schedules of its grant programs. Total giving by fiscal year: FY2019 $8.1M, FY2020 $9.8M, FY2021 $24.9M, FY2022 $10.6M, FY2023 $26.2M. The high-giving years (2021, 2023) correspond to large cohorts of multi-year SVRF grants entering their disbursement cycles simultaneously. The pattern suggests applicants should expect disbursements spread over three fiscal years rather than a single lump sum, even when the headline award is up to $600,000.

Based on documented grants in the foundation's records (105 total grants, $20.2M total): the median grant size is $198,338, average is $192,301, range runs from $41,124 (Tools & Technology Expansion Award) to $1,200,000 (Innovation Award to J. David Gladstone Institutes). The $50,000 Expansion Award represents the lower tier. SVRF Independent Investigator grants typically disburse in three annual installments averaging $140,000–$200,000 per year.

By program area, nearly all grants are concentrated in biomedical research. The organization does not fund advocacy, patient services, or health education. The Single Ventricle Research Fund accounts for the largest share of documented grants (~60 of the 105 recorded), followed by Tools & Technology Expansion Awards (~15 grants at $50,000 each) and Catalyst to Independence Awards (~6 grants at up to $200,000 per year over 5 years).

Geographically, California leads with 24 grants (largely Stanford, UCSD, UCSF, Children's Hospital LA), followed by Massachusetts with 17 grants (Boston Children's Hospital, Harvard, MIT, MGH). Ohio (8 grants, primarily Nationwide Children's), Colorado (7 grants, University of Colorado), and Maryland (7 grants) round out the top five states. International grants have been awarded (University of Oxford, Università degli Studi di Torino), demonstrating openness to global applicants with strong SV credentials. Total assets reached $220.3M in FY2024 on $29.1M in revenue, providing the balance-sheet capacity to sustain $20–$26M annual giving for the foreseeable future.

The peers listed in foundation databases are matched by asset size (~$220M) within the Philanthropy & Grantmaking NTEE category, not by programmatic focus. Additional Ventures is unique among this peer set in being a single-disease research funder with a fully open application process.

Among the peer set, Additional Ventures stands apart in three critical ways. First, it publishes open RFPs with specific eligibility criteria, deadlines, and scoring rubrics — making it one of the most transparent funders of comparable asset size. Second, its total giving as a share of assets (roughly 10–13% in high years) exceeds typical private foundation payout minimums, reflecting active philanthropic intent rather than asset preservation. Third, it has built a formal grant management infrastructure including ProposalCentral, independent peer review, and annual convening events that resemble an NIH study section model more than a traditional family foundation. Researchers accustomed to federal grant applications will find Additional Ventures' process familiar, though the organization's focused mission demands tighter topical alignment than most federal mechanisms.

The most consequential recent development is the launch of the Translational Accelerator program in 2024–2025, which adds a device and therapeutic innovation track to Additional Ventures' historically basic-science-oriented portfolio. The CTIP + Additional Ventures Device Innovation Award (up to $1M milestone-driven, approximately 3 years) accepted LOIs through November 6, 2025, with full proposals due February 26, 2026. This program is co-administered with CTIP (Center for Technology & Innovation in Pediatrics) and is open to companies as well as academic institutions — a significant shift for an organization that had previously funded only academic research teams.

The 2025 Expansion Award cycle selected 13 projects spanning neuroscience, stem cell biology, 3D bioprinting, and computational simulation. Notable awardees included Vahid Serpooshan at Emory University (3D bioprinted liver disease model for Fontan patients) and Nicole Dubois at Mount Sinai (fetal SV heart cellular characterization). The explicit welcome of researchers new to the SV space — 31% of 2025 recipients — signals the organization's intent to broaden the investigator pipeline.

The Single Ventricle Source genomics registry (Project Singular) is launching in 2025 after two years of platform development with IQVIA and Gencove. The registry targets 5,000+ whole-genome-sequenced participants and will make deidentified data freely available to qualified researchers worldwide via a simple application. Future grant applications that propose to contribute data to or leverage this registry will be at a competitive advantage.

The 2026 SVRF LOI deadline has passed (October 8, 2025). The next entry point is the Single Ventricle Investigator Meeting, October 7–9, 2026 in Denver, CO, which serves as both a scientific conference and an informal relationship-building opportunity with Additional Ventures program staff ahead of the 2027 SVRF cycle.

Know the program tier before drafting anything. Additional Ventures runs five distinct programs with separate eligibility, amounts, and portals. Misapplying to the wrong program is the most common first-time mistake. New researchers to the SV field should apply to the Expansion Award ($50,000) first. Early-career postdoctoral fellows should target the Catalyst to Independence Award (up to $1M over 5 years). Established investigators should apply via the SVRF. Device and therapeutic developers should pursue the Translational Accelerator.

Anchor every aim to SV patient outcomes. The scoring rubric rewards proposals that trace a direct line from your scientific question to long-term morbidity and mortality in single ventricle patients. The foundation explicitly prioritizes research on lymphatic dysfunction, Fontan-associated liver disease (FALD), kidney/gut perfusion, heart failure, valve dysfunction, arrhythmia, and neurodevelopmental sequelae. Proposals that address SV biology in isolation without connecting to these patient-level outcomes score lower.

Collaborative proposals earn bonus consideration in the SVRF. The Independent Investigator Track explicitly encourages multi-PI teams (up to 5 co-investigators). If your institution already has an active SV researcher — particularly at Boston Children's Hospital, Stanford, Nationwide Children's, or University of Colorado — a co-investigator relationship strengthens the application substantively and signals community integration.

Submit your LOI on ProposalCentral by 5 pm PST on the October deadline. The portal requires pre-registration. Do not wait until the day of. Full proposal invitations go out approximately 6 weeks after the LOI deadline; non-invited applicants receive no feedback on LOIs.

Leverage the open dataset. Proposals that incorporate or commit to contributing data to the Single Ventricle Source registry (launched 2025) align with a stated organizational priority and differentiate your application.

Attend SVIM in Denver (October 7–9, 2026) before the next application cycle opens. The organization's program staff and scientific advisory board are present, and the small size of the SV community means informal conversations meaningfully shape review outcomes.