Funding profile · RNA therapeutics delivery

Sixfold Bioscience

One Form D, thirteen investors, $2.27 million on the SEC record, a larger UK grant record, and filed accounts showing cash at £53,713 and headcount at eight.

$10.5MTotal capital at the Dec 2021 seed close, dilutive and non-dilutive combined, company-reported
$2.27MSold of $2,266,100 offered, the only Form D, filed Aug 2021
£1.73MInnovate UK grant offers across 12 projects led by Sixfold
£53,713Cash at bank at Dec 31, 2025, against £736,433 at Dec 31, 2022

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

Rounds at a glance

When Round Amount Investors Source
Feb 2021 first sale Seed, on SAFEs $2,266,100 sold of $2,266,100 13, not named Form D
Dec 2, 2021 Seed close announced $2.2M second close; $10.5M stated total Cantos Ventures, Y Combinator, Lombard Street Ventures, Pi Campus, angels Company release
2019 to 2029 Public grants and fellowships About £1.73M Innovate UK grant offers, £152,129 EU, three UKRI fellowships Innovate UK, European Commission, UKRI Gateway to Research
2022 to 2025 Capital contributions into the UK entity Reserve £3.13M to £5.75M, then £5.74M Sixfold Bioscience Inc. Filed accounts
Aug to Oct 2024 Secured facility, all monies Not disclosed Rocking Horse Solutions UK Limited Charge register
Since Aug 2021 No further Form D Nothing filed None on record Not found

What the filings show

Sixfold Bioscience Inc. · Form D · filed Aug 6, 2021

First sale
Feb 23, 2021
Offered
$2,266,100
Sold
$2,266,100 · $0 remaining
Investors
13 · average about $174,315
Security
A security to be acquired on exercise of a right, not equity
Exemption
Rule 506(b)
Issuer detail
Delaware corporation, incorporated 2017, address Walnut, California; revenue range declined
Related persons
Anna Perdrix Rosell (executive officer, director, promoter); George William Foot (executive officer, director, promoter); Tina Flatau (director, promoter)
Filing
SEC EDGAR, CIK 0001877208

Reading the filings

  1. The round was almost certainly SAFEs, and it is still not converted.The Form D marks the security type as one acquired on exercise of a right rather than equity. Four years later the UK accounts say: “In Sixfold Bioscience Inc, SAFE financing has been received in relation to agreements for pre and post-money equity caps, but no equity has yet been issued.” That is the same statement in the 2023, 2024 and 2025 accounts.
  2. The filing came four months before the announcement.First sale February 23, 2021, Form D filed August 6, 2021, press release December 2, 2021 describing “This most recent second close of the seed financing raised $2.2 million USD”. The $2,266,100 on the Form D and the $2.2 million in the release are the same money, and it had been in the door for nine months by the time it was announced.
  3. The $10.5 million is not an equity figure.The release calls it the “total dilutive and non-dilutive capital raised”. Innovate UK grant offers with fund start dates before 2022 come to about £695,000, plus £152,129 from the EU PROPEL project and a £852,747 fellowship that began in February 2021. Coverage generally presented $10.5M as venture funding.
  4. Five years of silence at the SEC.CIK 0001877208 holds one filing, the August 2021 Form D, with no amendment and nothing since. That is not proof no money moved: a raise under Section 4(a)(2) files no Form D. It does mean no Regulation D offering has been reported in five years.
  5. The UK books show the funding tap closing.The capital contribution reserve, which the accounts describe as a contribution from the parent, rose £1,654,420 in 2023 and £970,000 in 2024. In 2025 it fell £8,282. Cash at bank went £736,433, £542,200, £203,436, £53,713 across the same four year ends.
  6. Cost came out before the cash ran down.Average monthly headcount was 26 in 2023, 23 in 2024 and 8 in 2025. Equipment costing £166,509 was disposed of in 2025. Accumulated losses grew £2.57M in 2023, £2.24M in 2024 and £469,434 in 2025, so spending fell by roughly four fifths.
  7. A short, secured bridge in 2024.Charge 1068 7784 0001 was created on August 8, 2024 in favour of Rocking Horse Solutions UK Limited, fixed and floating over the whole undertaking, and satisfied in full on October 14, 2024. A two month secured facility is the shape of a grant or tax credit advance, not growth capital.

Commercial signals

Signal Detail Source type
Stage Preclinical. No trial sponsored by Sixfold appears in ClinicalTrials.gov as of Sep 22, 2026. Public record
Revenue Trade debtors of £12,096 at Dec 31, 2025, against nil the year before. No profit and loss account is filed, so revenue is not disclosed. Public record
Partnerships Wellcome Leap R3 and Innovate UK consortia with Medicines Discovery Catapult, Pharmidex and CPI. Funded research programmes. No licence, option or milestone deal announced. Public record
Licensing A co-founder CV states that “kidney assets are now in licensing discussions” following a strategic transaction process with external advisors. No counterparty or terms disclosed. Company-stated
IP Three granted US patents, the most recent dated Nov 18, 2025, and an application published Jul 16, 2026. IP work continued after the headcount fell. Public record
Control The Delaware parent ceased to be a person with significant control on May 28, 2025. The accounts signed Feb 17, 2026 still describe it as controlling the company throughout 2025. Records differ

What to watch

  • A Form D or an amendment under CIK 0001877208, which would show the SAFEs converting or a new raise.
  • The accounts to December 31, 2026, due by September 30, 2027.
  • Whether the kidney licensing discussions yield a named counterparty.
  • Fellowship MR/V026674/1 ended September 4, 2026. MR/Y018850/1 runs to April 2028.

The Sixfold Bioscience story on Healthcare DiscoveryHealthcare Discovery

Related companies

  • Nabla Bio: Shared investor: Cantos Ventures. A Cambridge company that writes antibodies on a computer and tests them in its own lab, aimed at the cell surface proteins conventional discovery keeps missing
  • XGenomes: Shared investor: Cantos Ventures. A Cambridge, Massachusetts company reading DNA in five letter words instead of one base at a time
  • Arpeggio Bio: Also in Drug Discovery and Delivery. A Boulder, Colorado biotech that read the transcriptome to find drugs for targets long called undruggable
  • Algen Biotechnologies: Also in Drug Discovery and Delivery. A CRISPR and machine learning platform for choosing drug targets, spun out of Jennifer Doudna’s Berkeley lab in 2018

Sources

  1. Public recordForm D, Sixfold Bioscience Inc., CIK 0001877208SEC EDGAR · Aug 6, 2021
  2. Public recordSIXFOLD BIOSCIENCE LTD. unaudited financial statements for 2023, 2024 and 2025Companies House · filed Mar 2024, Mar 2025, Feb 2026
  3. Public recordSIXFOLD BIOSCIENCE LTD. filing history and persons with significant controlCompanies House · accessed Sep 22, 2026
  4. Public recordMR01 registration of charge 1068 7784 0001, Rocking Horse Solutions UK LimitedCompanies House · Aug 9, 2024
  5. Public recordGateway to Research project records for SIXFOLD BIOSCIENCE LTD.UK Research and Innovation · refreshed Jul 6, 2026
  6. Public recordPatents assigned to Sixfold Bioscience Ltd.Justia Patents · accessed Sep 22, 2026
  7. IndependentSixfold bags VC funding to expand RNA delivery beyond the liverFierce Pharma, Nick Paul Taylor · Dec 7, 2021
  8. IndependentSixfold Bioscience company profile, employee count as at Jun 30, 2026Tracxn · accessed Sep 22, 2026
  9. CompanySixfold Bioscience completes $10.5M USD seed financingBusiness Wire and BioIndustry Association · Dec 2, 2021
  10. CompanyAnna Perdrix Rosell, personal professional profileannaperdrix.vercel.app · accessed Sep 22, 2026

Compiled from SEC, Companies House, UK Research and Innovation and other 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. UK grant figures are offer values recorded on Gateway to Research, not cash received. Healthcare Venture Capital Fund holds no position in Sixfold Bioscience. This page is not an offer to sell or a recommendation to buy any security.