Third Rock sells 697,500 RAPP shares in two transactions

Third Rock Ventures V, L.P. reported Rule 144 notices covering recent resale activity in the issuer's common stock.

Rhea-AI Filing Summary

Third Rock Ventures V, L.P. reported Rule 144 notices covering recent resale activity in the issuer's common stock. The filing lists sales of 426,005 shares on 04/17/2026 for $17,175,115.78 and 271,495 shares on 05/07/2026 for $47,826,929.00. The record also shows an original issuance of 2,803,200 shares on 02/21/2023 to the issuer for cash.

Insights

Securities Compliance Analyst

Rule 144 resale notices filed for two dated sales by Third Rock Ventures V, L.P.

The filing lists two resale transactions under Rule 144 with explicit sale dates and dollar proceeds. This is a regulatory notice that provides transfer details required for covered persons selling restricted or control securities.

Timing and dollar amounts are disclosed here; cash‑flow treatment indicates proceeds to the selling holder. Subsequent filings may show whether additional resale capacity remains.

Private Equity Investor Relations

Portfolio holder disclosed sizeable secondary sales; original issuance shown.

The notice shows an original issuance of 2,803,200 shares on 02/21/2023, then two reported sales in 04/2026 and 05/2026. These entries document liquidity events by the holder rather than company raises.

Investor relations impact is routine disclosure; market effect depends on trading context outside this excerpt.

Key Figures

Sale on 04/17/2026: 426,005 shares Proceeds 04/17/2026: $17,175,115.78 Sale on 05/07/2026: 271,495 shares +3 more

6 metrics

Sale on 04/17/2026 426,005 shares sale date 04/17/2026

Proceeds 04/17/2026 $17,175,115.78 amount shown alongside 426,005 shares

Sale on 05/07/2026 271,495 shares sale date 05/07/2026

Proceeds 05/07/2026 $47,826,929.00 amount shown alongside 271,495 shares

Original issuance 2,803,200 shares original issuance date 02/21/2023 to issuer for cash

Aggregate identifier 47,826,929 numeric string present in excerpt (context unclear)

Key Terms

Form 144, Original Issuance, Rule 144, Issuer

4 terms

Form 144 regulatory

"144: Securities To Be Sold"

Form 144 is a document that investors must file with the government when they plan to sell a large number of shares of a company's stock. It helps ensure transparency so everyone knows how many shares are being sold and when, which can impact the stock's price.

Original Issuance financial

"Common | 02/21/2023 | Original Issuance"

Rule 144 regulatory

"Securities Sold During The Past 3 Months"

Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

Issuer financial

"Original Issuance | Issuer | ... | 2803200"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What sales does the RAPP Form 144 list for Third Rock Ventures V, L.P.?

The Form 144 lists sales of 426,005 shares on 04/17/2026 for $17,175,115.78 and 271,495 shares on 05/07/2026 for $47,826,929.00. These entries identify the selling holder, dates, share counts, and dollar amounts as shown.

Does the filing show how the shares were originally issued for RAPP?

Yes. The excerpt shows an original issuance of 2,803,200 shares on 02/21/2023 to the issuer for cash. The line is labeled "Original Issuance" with the issuance date and share count as provided.

Who is the reported selling stockholder in this RAPP filing?

The selling holder named is Third Rock Ventures V, L.P. with an address listed at 201 Brookline Ave, Ste 1401, Boston, MA 02215. That entity is tied to the two resale entries shown in the excerpt.

Do the listed dollar amounts reflect proceeds to the company?

No. The amounts shown alongside the resale rows represent proceeds associated with the selling holder's sales. The excerpt identifies the transactions as resales by Third Rock Ventures V, L.P., not primary proceeds to the issuer.

What is the filing type and purpose for this RAPP submission?

This is a Form 144 notice, used to notify the SEC and broker-dealers of expected sales of restricted or control securities under Rule 144. The filing lists the shares, dates, and monetary amounts for compliance and transfer processing.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 05/08/2026 - 04:57 PM Learn about SEC filing dates

Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0001778071
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	Rapport Therapeutics, Inc.
SEC File Number	001-42121
Address of Issuer	99 HIGH STREET SUITE 2100 BOSTON MASSACHUSETTS 02110
Phone	857-321-8020
Name of Person for Whose Account the Securities are To Be Sold	Third Rock Ventures V, L.P.
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	10% Stockholder

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Common	Raymond James & Associates 880 Carillon Parkway St. Petersburg FL 33716	5018	202254.50	47826929	05/08/2026	NASDAQ

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Common	02/21/2023	Original Issuance	Issuer			2803200	02/21/2023	Cash

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Name and Address of Seller	Title of Securities Sold	Date of Sale	Amount of Securities Sold	Gross Proceeds
Third Rock Ventures V, L.P 201 Brookline Ave Ste 1401 Boston MA 02215	Common	04/17/2026	426005	17175115.78
Third Rock Ventures V, L.P 201 Brookline Ave Ste 1401 Boston MA 02215	Common	05/07/2026	271495	47826929.00

144: Remarks and Signature

Remarks
Date of Notice	05/08/2026
Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1	11/21/2025
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	Rashida Mitchell, as duly authorized representative of Raymond James & Associates, Inc., as attorney-in-fact for Third Rock Ventures V L.P.
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)