On what share count is RA Capital’s 19.9% VOR ownership based?

The 19.9% figure is calculated using 54,185,582 Vor Biopharma common shares outstanding as of March 30, 2026, as reported in the company’s Form 8-K. The calculation also gives effect to warrants and stock options that are exercisable within 60 days of the filing date.

Vor Biopharma (VOR) ownership update shows RA Capital at 19.9%

Filing Impact

(Moderate)

Filing Sentiment

(Neutral)

Form Type

SCHEDULE 13D/A

Rhea-AI Filing Summary

RA Capital Management and affiliates filed Amendment No. 13 to update their ownership in Vor Biopharma Inc. They report beneficial ownership of 12,187,524 shares of common stock, representing 19.9% of the class, calculated on 54,185,582 shares outstanding as of March 30, 2026.

The change reflects an increase in Vor Biopharma’s outstanding shares rather than new purchases or sales by the reporting persons. The position includes common stock, common stock warrants for up to 1,056,072 shares, pre-funded warrants for up to 10,000,000 shares, and stock options held for the benefit of RA Capital, all subject to beneficial ownership blockers that limit exercise above specified ownership caps.

Key Figures

Beneficial ownership: 12,187,524 shares Ownership percentage: 19.9% Shares outstanding: 54,185,582 shares +5 more

8 metrics

Beneficial ownership 12,187,524 shares Shares of Vor Biopharma common stock beneficially owned by reporting persons

Ownership percentage 19.9% Percent of Vor Biopharma common stock class represented by 12,187,524 shares

Shares outstanding 54,185,582 shares Vor Biopharma common stock outstanding as of March 30, 2026

Fund common shares 5,404,998 shares Common stock directly held by RA Capital Healthcare Fund, L.P.

Common stock warrants 1,056,072 shares Shares underlying common stock warrants held by the fund

Pre-funded warrants 10,000,000 shares Shares underlying pre-funded warrants held by the fund

Stock options for Resnick 6,190 shares Common stock underlying vested options held for RA Capital’s benefit

Option exercise price $12.80/share Exercise price for option of which 83 shares vested on May 18, 2026

Key Terms

pre-funded warrants, Beneficial Ownership Blocker, Schedule 13D, stock options (right to buy), +2 more

6 terms

pre-funded warrants financial

"pre-funded warrants (the "Pre-Funded Warrants" and, together with the Common Stock Warrants, the "Warrants") exercisable for up to 10,000,000 shares"

Pre-funded warrants are financial instruments that give investors the right to purchase a company's stock at a set price, but with most or all of the purchase price paid upfront. They function like a coupon or gift card for stock, allowing investors to buy shares later at a fixed price, which can be beneficial if they want to avoid future price increases. This makes them important for investors seeking flexibility and certainty in their investment plans.

Beneficial Ownership Blocker financial

"The Common Stock Warrants contain a provision (the "Common Stock Warrant Beneficial Ownership Blocker") which precludes exercise"

Schedule 13D regulatory

"amends and supplements the statement on originally filed with the Securities and Exchange Commission ... by the Reporting Persons"

A Schedule 13D is a legal document that investors file with regulators when they buy a large enough stake in a company to potentially influence its management or decisions. It provides details about the investor’s intention, ownership stake, and plans, helping other investors understand who is gaining control and what their motives might be.

stock options (right to buy) financial

"common stock underlying vested stock options (right to buy) held by Joshua Resnick for the benefit of RA Capital"

Current Report on Form 8-K regulatory

"as reported in the Issuer's Current Report on Form 8-K filed with the SEC on March 27, 2026"

A current report on Form 8-K is a document that publicly traded companies file to promptly share important news or events that could affect their financial position or stock price, such as major business changes or legal issues. It helps investors stay informed about timely developments, allowing them to make better decisions about buying or selling shares.

beneficial owner regulatory

"may be deemed a beneficial owner, for purposes of Section 13(d) of the Act, of any securities of the Issuer"

A beneficial owner is the person who ultimately owns or controls a financial asset or property, even if their name isn't directly on official documents. Think of it like someone who secretly holds the keys to a safe deposit box—others may appear to have access, but the true owner is the one who benefits from what's inside. Identifying beneficial owners helps ensure transparency and prevent illegal activities like money laundering or fraud.

04/01/2026 - 05:09 PM

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 13)

VOR BIOPHARMA INC.

(Name of Issuer)

Common Stock, par value $0.0001 per share

(Title of Class of Securities)

929033207

(CUSIP Number)

Peter Kolchinsky
RA Capital Management, L.P., 200 Berkeley Street, 18th Floor
Boston, MA, 02116
617.778.2500

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

03/30/2026

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

SCHEDULE 13D

Item 1.

Security and Issuer

(a)

Title of Class of Securities:

Common Stock, par value $0.0001 per share

(b)

Name of Issuer:

VOR BIOPHARMA INC.

(c)

Address of Issuer's Principal Executive Offices:

500 Boylston Street, Suite 1350, Boston, MASSACHUSETTS , 02116.

Item 1 Comment:

This Amendment No. 13 (this "Amendment No. 13" or this "Schedule 13D/A") amends and supplements the statement on Schedule 13D originally filed with the Securities and Exchange Commission (the "SEC") on February 19, 2021, and amended on November 14, 2022, December 9, 2022, August 11, 2023, December 30, 2024, June 27, 2025, September 19, 2025, October 20, 2025, October 27, 2025, October 30, 2025, November 14, 2025, December 18, 2025 and March 16, 2026 (as amended, the "Statement") by the Reporting Persons. This Amendment No. 13 is being filed to report the increase in the number of shares of the Issuer's common stock deemed to be beneficially owned by the Reporting Persons as a result of the increase in the outstanding shares of the Issuer's common stock and not as a result of any acquisition or disposition of securities by the Reporting Persons. Unless otherwise defined herein, capitalized terms used in this Amendment No. 13 shall have the meanings ascribed to them in the Statement. Unless amended or supplemented below, the information in the Statement remains unchanged.

Item 2.

Identity and Background

(a)

This Schedule 13D/A is being filed on behalf of RA Capital Management, L.P. ("RA Capital"), Peter Kolchinsky, Rajeev Shah, and RA Capital Healthcare Fund, L.P. (the "Fund"). RA Capital, Dr. Kolchinsky, Mr. Shah and the Fund are collectively referred to herein as the "Reporting Persons." The agreement among the Reporting Persons to file this Schedule 13D/A jointly in accordance with Rule 13d-1(k) of the Securities Exchange Act of 1934, as amended, (the "Act") is attached hereto as Exhibit 99.1. The Reporting Persons' beneficial ownership of the Issuer's common stock consists of (i) 5,404,998 shares of common stock directly held by the Fund; (ii) Common Stock Warrants exercisable for up to 1,056,072 shares of common stock held directly by the Fund; (iii) pre-funded warrants (the "Pre-Funded Warrants" and, together with the Common Stock Warrants, the "Warrants") exercisable for up to 10,000,000 shares of common stock directly held by the Fund; (iv) a total of 6,190 shares of common stock underlying vested stock options (right to buy) held by Joshua Resnick for the benefit of RA Capital; and (v) a total of 249 shares of common stock underlying vested stock options (right to buy) and 167 shares of common stock underlying stock options (right to buy) scheduled to vest within 60 days of this filing held by Andrew Levin for the benefit of RA Capital. The Common Stock Warrants contain a provision (the "Common Stock Warrant Beneficial Ownership Blocker") which precludes exercise of the Common Stock Warrants to the extent that, following exercise, the Fund, together with its affiliates and other attribution parties, would own more than 9.99% of the common stock outstanding. The Fund is currently prohibited from exercising the Common Stock Warrants by virtue of the Common Stock Warrant Beneficial Ownership Blocker. The Pre-Funded Warrants contain a provision (the "Pre-Funded Warrant Beneficial Ownership Blocker") which precludes exercise of the Pre-Funded Warrants to the extent that, following exercise, the Fund, together with its affiliates and other attribution parties, would own more than 19.99% of the common stock outstanding. The Fund is currently prohibited from exercising the Pre-Funded Warrants to the extent that such exercise would result in beneficial ownership of more than 12,187,524 shares of common stock by virtue of the by virtue of the Pre-Funded Warrant Beneficial Ownership Blocker. RA Capital Healthcare Fund GP, LLC is the general partner of the Fund. The general partner of RA Capital is RA Capital Management GP, LLC, of which Dr. Kolchinsky and Mr. Shah are the controlling persons. RA Capital serves as investment adviser for the Fund and may be deemed a beneficial owner, for purposes of Section 13(d) of the Act, of any securities of the Issuer held by the Fund. The Fund has delegated to RA Capital the sole power to vote and the sole power to dispose of all securities held in its portfolio, including the shares of the Issuer's common stock reported herein. Because each of the Fund has divested itself of voting and investment power over the reported securities it holds and may not revoke that delegation on less than 61 days' notice, the Fund disclaims beneficial ownership of the securities it holds for purposes of Section 13(d) of the Act and therefore disclaims any obligation to report ownership of the reported securities under Section 13(d) of the Act. As managers of RA Capital, Dr. Kolchinsky and Mr. Shah may be deemed beneficial owners, for purposes of Section 13(d) of the Act, of any securities of the Issuer beneficially owned by RA Capital. RA Capital, Dr. Kolchinsky, and Mr. Shah disclaim beneficial ownership of the securities reported in this Schedule 13D/A other than for the purpose of determining their obligations under Section 13(d) of the Act, and the filing of this Schedule 13D/A shall not be deemed an admission that either RA Capital, Dr. Kolchinsky, or Mr. Shah is the beneficial owner of such securities for any other purpose.

(b)

The address of the principal business office of each of the Reporting Persons is 200 Berkeley Street, 18th Floor, Boston, MA 02116.

(c)

The Fund is a private investment vehicle. RA Capital provides investment management services to the Fund. The principal occupation of each of Dr. Kolchinsky and Mr. Shah is investment management.

(d)

During the last five years, none of the Reporting Persons has been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors).

(e)

During the last five years, none of the Reporting Persons has been a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding was or is subject to a judgment, decree of final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

(f)

See Item 6 of the cover pages.

Item 5.

Interest in Securities of the Issuer

(a)

Rows 11 and 13 of each Reporting Person's cover page to this Schedule 13D/A set forth the aggregate number of shares of common stock and percentages of the shares of common stock beneficially owned by such Reporting Person and are incorporated by reference. The percentage set forth in each row 13 is based upon 54,185,582 shares of common stock outstanding as of March 30, 2026, as reported in the Issuer's Current Report on Form 8-K filed with the SEC on March 27, 2026, and giving effect to Warrants and stock options, to the extent exercisable within 60 days hereof, as referenced herein. Due to field limitations of the EDGAR filing system, the percentage listed in Row 13 of each of the cover pages has been rounded down to 19.9%.

(b)

Rows 7 through 10 of each Reporting Person's cover page to this Schedule 13D/A set forth the number of shares of common stock as to which such Reporting Person has the sole or shared power to vote or direct the vote and sole or shared power to dispose or to direct the disposition and are incorporated by reference.

(c)

Except as set forth below, none of the Reporting Persons has effected any transactions with respect to the securities of the Issuer since the most recent amendment to this Schedule 13D/A. No. Price Per Transaction Seller Date Shares Share ($) Vest Stock Option (Right to Buy) Fund 05/18/2026 83 (1) (2) (1) This option represents a right to purchase a total of 3,000 shares of the Issuer's common stock, which began vesting from December 18, 2025 in 36 monthly installments. The vesting of the option is subject to Dr. Levin's continuous service to the Issuer through each vesting date. This option has an exercise price of $12.80 per share. (2) Represents future vesting options within 60 days from the filing date of this Schedule 13D/A.

(d)

No person (other than the Reporting Persons) is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the securities subject to this Schedule 13D/A.

(e)

Not applicable.

Item 7.

Material to be Filed as Exhibits.

Exhibit 99.1 Joint Filing Agreement (incorporated by reference to Exhibit 99.1 to the Reporting Persons' Schedule 13D/A filed with the SEC on June 27, 2025).

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

RA Capital Management, L.P.

Signature:	/s/ Peter Kolchinsky
Name/Title:	By Peter Kolchinsky, Manager
Date:	04/01/2026

Peter Kolchinsky

Signature:	/s/ Peter Kolchinsky
Name/Title:	Peter Kolchinsky
Date:	04/01/2026

Rajeev Shah

Signature:	/s/ Rajeev Shah
Name/Title:	Rajeev Shah
Date:	04/01/2026

RA Capital Healthcare Fund, L.P.

Signature:	/s/ Peter Kolchinsky
Name/Title:	By RA Capital Healthcare Fund GP, LLC, its General Partner, By Peter Kolchinsky, Manager
Date:	04/01/2026

Source: View Original Filing on SEC EDGAR

FAQ

What ownership stake in VOR does RA Capital report in this Schedule 13D/A?

RA Capital and related reporting persons report beneficial ownership of 12,187,524 shares of Vor Biopharma common stock, equal to 19.9% of the class. This percentage is based on 54,185,582 shares outstanding as of March 30, 2026, including exercisable warrants and options.

Did RA Capital buy or sell additional VOR shares in this Schedule 13D/A?

The amendment states the increased beneficial ownership results from a higher number of Vor Biopharma shares outstanding, not from acquisitions or dispositions by RA Capital. The only transaction disclosed is vesting of 83 stock options on May 18, 2026 at a $12.80 exercise price.

How is RA Capital’s VOR position structured between stock, warrants, and options?

The reported stake includes 5,404,998 Vor Biopharma common shares, common stock warrants exercisable for up to 1,056,072 shares, pre-funded warrants for up to 10,000,000 shares, and small blocks of stock options for Joshua Resnick and Andrew Levin held for RA Capital’s benefit, subject to vesting and ownership limits.

What are the beneficial ownership blockers affecting RA Capital’s VOR warrants?

The common stock warrants cannot be exercised if doing so would push the fund above 9.99% ownership. The pre-funded warrants similarly block exercises that would take ownership above 19.99%, and currently restrict exercises that would exceed 12,187,524 common shares beneficially owned in total.

Who are the reporting persons in this VOR Schedule 13D/A amendment?

The reporting persons are RA Capital Management, L.P., RA Capital Healthcare Fund, L.P., and individuals Peter Kolchinsky and Rajeev Shah. RA Capital acts as investment adviser to the fund, and Kolchinsky and Shah are controlling persons of RA Capital’s general partner, with certain beneficial ownership disclaimers noted.