Third Rock fund sells 133,618 Rapport shares

Third Rock Ventures V, L.P. reported an open-market sale of 133,618 shares of Rapport Therapeutics, Inc. common stock on May 11, 2026 at a weighted average price of $40.244 per share.

Rhea-AI Filing Summary

Third Rock Ventures V, L.P. reported an open-market sale of 133,618 shares of Rapport Therapeutics, Inc. common stock on May 11, 2026 at a weighted average price of $40.244 per share. The sale occurred in multiple trades between $40.00 and $40.665 per share under a previously adopted Rule 10b5-1 trading plan.

After this transaction, Third Rock Ventures V directly held 6,299,097 shares of Rapport Therapeutics common stock. A related fund, Third Rock Ventures VI, L.P., is reported as holding an additional 969,218 shares indirectly, with the general partner entities disclaiming beneficial ownership except to the extent of any pecuniary interest.

Insider Trade Summary 10b5-1

Net Seller: 133,618 shares

Net Sell 2 txns

Insider Third Rock Ventures V, L.P., Third Rock Ventures GP V, LP, TRV GP V, LLC, Third Rock Ventures VI, L.P., Third Rock Ventures GP VI, L.P., TRV GP VI, LLC

Role 10% Owner | 10% Owner | 10% Owner | 10% Owner | 10% Owner | 10% Owner

Sold 133,618 shs ($5.38M)

Type	Security	Shares	Price	Value
Sale	Common Stock	133,618	$40.244	$5.38M
holding	Common Stock	--	--	--

Holdings After Transaction: Common Stock — 6,299,097 shares (Direct); Common Stock — 969,218 shares (Indirect, By Third Rock Ventures VI, L.P.)

Footnotes (4)

1. F1. The reported transactions were effected pursuant to a Rule 10b5-1 trading plan dated November 21, 2025, previously adopted by the Reporting Person.
2. F2. The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $40.00 to $40.665, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (2).
3. F3. These shares are directly held by Third Rock Ventures V, L.P. ("TRV V"). The general partner of TRV V is Third Rock Ventures GP V, L.P. ("TRV GP V"). The general partner of TRV GP V is TRV GP V, LLC ("TRV GP V LLC"). Each of TRV GP V and TRV GP V LLC disclaims beneficial ownership of the shares except to the extent of its pecuniary interest therein, if any, and this report shall not be deemed an admission that it is the beneficial owner of such shares.
4. F4. The shares are held directly by Third Rock Ventures VI, L.P. ("TRV VI"). The general partner of TRV VI is Third Rock Ventures GP VI, L.P. ("TRV GP VI"). The general partner of TRV GP VI is TRV GP VI, LLC ("TRV GP VI LLC"). Each of TRV GP VI, and TRV GP VI LLC, disclaims beneficial ownership of these shares except to the extent of its pecuniary interest therein, if any, and this report shall not be deemed an admission that it is the beneficial owner of such shares. Each of Reporting Persons disclaims the existence of a Section 13(d) "group" as between any TRV V related parties and any TRV VI related parties and this report shall not be deemed an admission that any of such parties is or may be part of such a group with any of the other parties.

Key Figures

Shares sold: 133,618 shares Weighted average sale price: $40.244 per share Sale price range: $40.00–$40.665 per share +3 more

6 metrics

Shares sold 133,618 shares Open-market sale on May 11, 2026

Weighted average sale price $40.244 per share Common stock sale on May 11, 2026

Sale price range $40.00–$40.665 per share Multiple transactions in reported sale

Direct holdings after sale 6,299,097 shares Third Rock Ventures V, L.P. post-transaction position

Indirect holdings 969,218 shares Held by Third Rock Ventures VI, L.P.

Rule 10b5-1 plan date November 21, 2025 Plan governing the reported sales

Key Terms

Rule 10b5-1 trading plan, weighted average price, beneficial ownership, pecuniary interest, +1 more

5 terms

Rule 10b5-1 trading plan regulatory

"The reported transactions were effected pursuant to a Rule 10b5-1 trading plan dated November 21, 2025"

A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.

weighted average price financial

"The price reported is a weighted average price. These shares were sold in multiple transactions"

Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.

beneficial ownership regulatory

"disclaims beneficial ownership of the shares except to the extent of its pecuniary interest therein"

Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.

pecuniary interest financial

"disclaims beneficial ownership of the shares except to the extent of its pecuniary interest therein"

Section 13(d) "group" regulatory

"disclaims the existence of a Section 13(d) "group" as between any TRV V related parties and any TRV VI related parties"

FAQ

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

What did Third Rock Ventures report in its latest Form 4 for RAPP?

Third Rock Ventures V, L.P. reported selling 133,618 shares of Rapport Therapeutics common stock on May 11, 2026 at a weighted average price of $40.244 per share, executed as multiple trades within a narrow price range.

How many Rapport Therapeutics (RAPP) shares did Third Rock sell and at what prices?

Third Rock Ventures V, L.P. sold 133,618 shares of Rapport Therapeutics common stock at a weighted average of $40.244 per share, with individual trades priced between $40.00 and $40.665 per share, according to the Form 4 disclosure.

Was the Third Rock Ventures sale of RAPP shares under a Rule 10b5-1 plan?

Yes. The Form 4 states the reported transactions were effected pursuant to a Rule 10b5-1 trading plan dated November 21, 2025, previously adopted by the reporting person, indicating the sales were pre-arranged rather than discretionary.

How many Rapport Therapeutics shares does Third Rock Ventures hold after the sale?

Following the May 11, 2026 sale, Third Rock Ventures V, L.P. directly held 6,299,097 shares of Rapport Therapeutics common stock. A related fund, Third Rock Ventures VI, L.P., is reported as holding an additional 969,218 shares indirectly.

Which Third Rock entities are associated with the RAPP share holdings?

Shares are directly held by Third Rock Ventures V, L.P. and Third Rock Ventures VI, L.P. Their respective general partners—Third Rock Ventures GP V, L.P., TRV GP V, LLC, Third Rock Ventures GP VI, L.P., and TRV GP VI, LLC—disclaim beneficial ownership except to any pecuniary interest.

What price details are disclosed for the Third Rock sale of RAPP stock?

The Form 4 reports a weighted average sale price of $40.244 per share. It notes the shares were sold in multiple transactions, with individual sale prices ranging from $40.00 to $40.665, and offers to provide full breakdowns upon request.

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

Form 4 Insider Transactions: What Each Field Means →

See more from StockTitan in Google Search and AI answers. Adds StockTitan as a preferred source · opens Google

Add on Google Not now

Accepted by SEC EDGAR 05/13/2026 - 07:06 PM Learn about SEC filing dates

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

X

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Third Rock Ventures V, L.P.

(Last) (First) (Middle)

C/O THIRD ROCK VENTURES, LLC

201 BROOKLINE AVE, SUITE 1401

(Street)

BOSTON MASSACHUSETTS 02215

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Rapport Therapeutics, Inc. [ RAPP ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/11/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

	Form filed by One Reporting Person
X	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	05/11/2026		S(1)		133,618	D	$40.244(2)	6,299,097	D(3)
Common Stock								969,218	I	By Third Rock Ventures VI, L.P.(4)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

1. Name and Address of Reporting Person^*

Third Rock Ventures V, L.P.

(Last) (First) (Middle)

C/O THIRD ROCK VENTURES, LLC

201 BROOKLINE AVE, SUITE 1401

(Street)

BOSTON MASSACHUSETTS 02215

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

1. Name and Address of Reporting Person^*

Third Rock Ventures GP V, LP

(Last) (First) (Middle)

201 BROOKLINE AVE, SUITE 1401

(Street)

BOSTON MASSACHUSETTS 02215

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

1. Name and Address of Reporting Person^*

TRV GP V, LLC

(Last) (First) (Middle)

201 BROOKLINE AVE, SUITE 1401

(Street)

BOSTON MASSACHUSETTS 02215

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

1. Name and Address of Reporting Person^*

Third Rock Ventures VI, L.P.

(Last) (First) (Middle)

C/O THIRD ROCK VENTURES, LLC

201 BROOKLINE AVE, SUITE 1401

(Street)

BOSTON MASSACHUSETTS 02215

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

1. Name and Address of Reporting Person^*

Third Rock Ventures GP VI, L.P.

(Last) (First) (Middle)

201 BROOKLINE AVE, SUITE 1401

(Street)

BOSTON MASSACHUSETTS 02215

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

1. Name and Address of Reporting Person^*

TRV GP VI, LLC

(Last) (First) (Middle)

201 BROOKLINE AVE, SUITE 1401

(Street)

BOSTON MASSACHUSETTS 02215

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

Explanation of Responses:

1. The reported transactions were effected pursuant to a Rule 10b5-1 trading plan dated November 21, 2025, previously adopted by the Reporting Person.

2. The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $40.00 to $40.665, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (2).

3. These shares are directly held by Third Rock Ventures V, L.P. ("TRV V"). The general partner of TRV V is Third Rock Ventures GP V, L.P. ("TRV GP V"). The general partner of TRV GP V is TRV GP V, LLC ("TRV GP V LLC"). Each of TRV GP V and TRV GP V LLC disclaims beneficial ownership of the shares except to the extent of its pecuniary interest therein, if any, and this report shall not be deemed an admission that it is the beneficial owner of such shares.

4. The shares are held directly by Third Rock Ventures VI, L.P. ("TRV VI"). The general partner of TRV VI is Third Rock Ventures GP VI, L.P. ("TRV GP VI"). The general partner of TRV GP VI is TRV GP VI, LLC ("TRV GP VI LLC"). Each of TRV GP VI, and TRV GP VI LLC, disclaims beneficial ownership of these shares except to the extent of its pecuniary interest therein, if any, and this report shall not be deemed an admission that it is the beneficial owner of such shares. Each of Reporting Persons disclaims the existence of a Section 13(d) "group" as between any TRV V related parties and any TRV VI related parties and this report shall not be deemed an admission that any of such parties is or may be part of such a group with any of the other parties.

	/s/ Kevin Gillis, Chief Operating Officer of TRV GP V, LLC, general partner of Third Rock Ventures GP V, L.P., general partner of Third Rock Ventures V, L.P.	05/13/2026
	/s/ Kevin Gillis, Chief Operating Officer of TRV GP V, LLC, general partner of Third Rock Ventures GP V, L.P.	05/13/2026
	/s/ Kevin Gillis, Chief Operating Officer of TRV GP V, LLC	05/13/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)