Funding profile · Consumer diagnostics

SiPhox Health

A Burlington, Massachusetts photonics company reporting $32 million raised. Its own Form D filings account for about $15 million of that, and the most recent is from January 2023.

$32MVenture money raised, company-reported to the Globe (Feb 2025)
$15.07MSum of amounts sold across SiPhox Inc. Form D filings
$12.5MSold of $15.0M offered on the January 2023 equity Form D
$3.06MRaised by two single-company SPVs filing their own Form Ds

Data as of September 22, 2026. Company-reported figures are labeled.

Rounds at a glance

When Round Amount Investors Source
Aug 2020 Post-money SAFE $810,000 of $2.0M, amended to $1.06M 17, then 19 Form D and D/A
2020 Y Combinator, summer cohort Not disclosed Y Combinator TechCrunch
Apr 2021 Post-money SAFE $10,000 1 Form D
Nov 2021 SAFE, filed under Biotechnology $1,500,000 1 Form D
Jan 2023 Equity offering $12,500,000 sold of $15,000,000 44 Form D
Jul 2023 Announced as $27M: $10M seed plus $17M Series A $27,000,000 announced Series A led by Intel Capital; seed co-led by Khosla Ventures and Y Combinator TechCrunch
Oct 2024 SPV: Starling Ventures SiPhox Health Ltd (BVI) $205,000 50, minimum $2,500 Form D
Mar to Sep 2026 SPV: SiPhox Series B lead Dec 2025, a Series of CGF2021 LLC $2,510,000, amended to $2,858,979 8, then 15; Sydecar Form D and D/A
Jul 2022 State grant, non-dilutive $681,631 Massachusetts Manufacturing Innovation Initiative Mass.gov

What the filings show

SiPhox Inc. · Form D · filed Jan 18, 2023

First sale
Jan 5, 2023
Offered
$15,000,000 equity
Sold
$12,500,000 · $2,500,000 remaining
Investors
44 · average about $284,091
Exemption
Rule 506(b)
Related persons
Diedrik Vermeulen and Michael Dubrovsky, both executive officer and director. Signed by Vermeulen as CEO
Use of proceeds
$294,000 estimated to executive salaries
Filing
SEC EDGAR, CIK 0001824002

SiPhox Inc. · earlier Form D filings · 2020 to 2021

Sep 16, 2020
SAFE, $810,000 of $2,000,000, 17 investors, first sale Aug 19, 2020
Dec 9, 2020
D/A on the same offering, $1,060,000 sold, 19 investors
Apr 20, 2021
SAFE, $10,000 offered and sold, 1 investor
Nov 16, 2021
SAFE, $1,500,000 offered and sold, 1 investor, filed under Biotechnology
Exemption
Rule 506(b) on all four
Filing
SEC EDGAR, CIK 0001824002

SiPhox Series B lead Dec 2025, a Series of CGF2021 LLC · Form D filed Mar 9, 2026, amended Sep 9, 2026

First sale
Mar 4, 2026
Type
Pooled investment fund, single company SPV
Sold
$2,510,000 at filing, amended to $2,858,979
Investors
8, then 15 · average about $190,599 on the amendment
Exemptions
Rule 506(b); Investment Company Act 3(c)(1)
Related persons
Sydecar LLC (administrator); Brett Sagan (officer of the administrator)
Filing
SEC EDGAR, CIK 0002103489

Reading the filings

  1. The announcement is larger than the filing.TechCrunch reported $27 million in July 2023, split as $10 million of seed and $17 million of new Series A. The only equity Form D on SiPhox’s CIK reports $15,000,000 offered and $12,500,000 sold, first sale January 5, 2023, filed six months before the announcement. No amendment moved that figure to $17 million.
  2. The checks are institutional size.$12,500,000 across 44 investors is about $284,091 each, consistent with a lead fund plus a tail of smaller participants rather than a crowd of angels.
  3. Roughly half the reported capital has no Form D behind it.The four SiPhox Inc. filings sum to $15,070,000 sold: $1,060,000 plus $10,000 plus $1,500,000 plus $12,500,000. The Globe reported $32 million raised. Issuers relying on Section 4(a)(2) file no Form D, so the roughly $17 million gap does not mean the money is absent. It means the record stops in January 2023.
  4. A Series B exists in the record only as a filename.SiPhox Inc. has filed nothing since January 2023. What discloses a Series B is a Sydecar vehicle called SiPhox Series B lead Dec 2025: $2,510,000 from 8 investors, first sale March 4, 2026, amended in September 2026 to $2,858,979 from 15. It is named for a December 2025 lead but sold three months later, the usual pattern for a syndicate assembling alongside a priced round.
  5. One vehicle is offshore and retail sized.Starling Ventures SiPhox Health Ltd, a British Virgin Islands company, sold $205,000 to 50 investors in October 2024, an average of $4,100 each against a $2,500 minimum. That is a different distribution channel from the 2023 round, and the filing names no manager beyond a corporate director.
  6. The board is the two founders.Every SiPhox Inc. filing lists only Vermeulen and Dubrovsky as related persons. Intel Capital said Srini Ananth joined the board with the Series A in July 2023; no later Form D exists to show it.

Commercial signals

Signal Detail Source type
Regulatory No 510(k) and no PMA. An FDA establishment registration and a listing for a blood specimen collection convenience kit, code PQD, which needs no premarket notification. Public record
Revenue model Membership at $124 for the first cycle and $149 after, plus a white label partner program with a 500 kit minimum. Company-stated
Cost of goods Samples run by an unnamed third-party CLIA certified, CAP accredited laboratory. The photonic chip that would bring that cost in-house is not cleared. Company-stated
Non-dilutive $681,631 Massachusetts M2I2 grant, July 2022, for biochip manufacturing capacity. No NIH or NSF award found. Public record
Competitive set Function Health raised $298 million at a $2.5 billion valuation in November 2025. Everlywell sells comparable mail-in panels. Independent

What to watch

  • A Form D from SiPhox Inc. for the Series B. One is due within 15 days of a first sale under Regulation D, and none has appeared.
  • Whether the $17 million Series A figure is ever reconciled with the $12.5 million on file.
  • A further amendment to the Sydecar SPV, showing the syndicate still filling.
  • Any filing that adds a director outside the two founders.
  • An FDA submission for SiPhox Home, which would change the unit economics.

The SiPhox Health story on Healthcare DiscoveryHealthcare Discovery

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Sources

  1. Public recordForm D and Form D/A, SiPhox Inc.SEC · Sep 16, 2020; Dec 9, 2020; Apr 20, 2021; Nov 16, 2021; Jan 18, 2023
  2. Public recordForm D and Form D/A, SiPhox Series B lead Dec 2025, a Series of CGF2021 LLCSEC · Mar 9, 2026 and Sep 9, 2026
  3. Public recordForm D, Starling Ventures SiPhox Health LtdSEC · Oct 31, 2024
  4. Public recordopenFDA registration, listing and classification records, SiPhox, Inc. and code PQDFDA · retrieved Sep 23, 2026
  5. Public recordBaker-Polito Administration Awards $681,000 Grant to Burlington’s SiPhoxMass.gov · Jul 13, 2022
  6. IndependentIntel Capital, Khosla lead $27M investment into SiPhox HealthTechCrunch, Christine Hall · Jul 19, 2023
  7. IndependentDo-it-yourself home blood tests may be available next yearThe Boston Globe, Hiawatha Bray · Feb 11, 2025
  8. IndependentFunction Health raises $298M Series B at $2.5B valuationTechCrunch · Nov 19, 2025
  9. CompanyInvesting in the Next Epoch of Personalized DiagnosticsIntel Capital · Jul 19, 2023
  10. CompanyPrograms, Partner and answers pagessiphoxhealth.com · accessed Sep 2026

Compiled from SEC, FDA and Massachusetts public records and published reports as of September 22, 2026. Form D notices report offerings under Regulation D; amounts reflect the filing date and may not capture later sales. Healthcare Venture Capital Fund holds no position in SiPhox Health. This page is not an offer to sell or a recommendation to buy any security.