Mark Mossler plans sale of 15,000 CCCC shares

Mark Mossler filed to sell 15,000 shares of Common Stock of CCCC through Morgan Stanley Smith Barney LLC Executive Financial Services on or after 08/13/2026, with an aggregate market value of $61,072.50 on NASDAQ.

Rhea-AI Filing Summary

Mark Mossler filed to sell 15,000 shares of Common Stock of CCCC through Morgan Stanley Smith Barney LLC Executive Financial Services on or after 08/13/2026, with an aggregate market value of $61,072.50 on NASDAQ. The shares were acquired via a stock option exercise paid in cash. Over the prior three months, Mossler reported additional Common Stock sales of 19,519 shares for $76,680.39 on 08/12/2026 and 9,087 shares for $35,484.74 on 05/27/2026.

Key Figures

Planned shares to be sold: 15,000 shares Aggregate market value of planned sale: $61,072.50 Recent sale 1: 19,519 shares for $76,680.39 +2 more

5 metrics

Planned shares to be sold 15,000 shares Common Stock sale planned on or after 08/13/2026

Aggregate market value of planned sale $61,072.50 Value of 15,000 Common shares to be sold via Morgan Stanley

Recent sale 1 19,519 shares for $76,680.39 Common Stock sale dated 08/12/2026

Recent sale 2 9,087 shares for $35,484.74 Common Stock sale dated 05/27/2026

Broker Morgan Stanley Smith Barney LLC Executive Financial Services Handling the planned sale of 15,000 shares

Key Terms

Form 144, stock option exercise, aggregate market value

3 terms

Form 144 regulatory

"Form 144 shows Mark Mossler planning to sell 15,000 CCCC shares"

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.

stock option exercise financial

"Common | 08/13/2026 | Stock Option Exercise | Issuer"

A stock option exercise is the act of using a previously granted right to buy shares of a company's stock at a specific, predetermined price by paying that price and receiving the shares. It matters to investors because exercising changes who owns the shares (which can dilute existing ownership), can trigger taxable events and shift potential gains or losses, and affects voting power and the company’s outstanding share count—like turning a voucher into an actual product that becomes part of circulating supply.

aggregate market value financial

"Common ... 15000 | 61072.50 | 123025136 | 08/13/2026"

Aggregate market value is the combined price you would pay to buy all outstanding shares of a company or all companies in a group at current market prices — essentially the sum of each stock’s market capitalization. It matters to investors because it shows the overall size and weight of an investment or sector (like the total cost to buy every piece of a puzzle), helps compare scale across companies or markets, and influences index composition and risk exposure.

FAQ

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

What share sale is disclosed for CCCC in this Form 144?

The filing discloses a planned sale of 15,000 shares of CCCC Common Stock, with an aggregate market value of $61,072.50, to be sold through Morgan Stanley Smith Barney LLC on or after 08/13/2026.

Who is the reporting person in the CCCC Form 144 filing?

The reporting person is Mark Mossler, listed with an address at 490 Arsenal Way, Suite 120, Watertown, MA 02472. He reports planned and recent sales of CCCC Common Stock under this Form 144 notice.

How were the 15,000 CCCC shares to be sold acquired?

The 15,000 shares of CCCC Common Stock were acquired through a stock option exercise from the issuer on 08/13/2026, with the form indicating the consideration for the exercise was paid in cash.

What recent CCCC stock sales has Mark Mossler reported?

In the past three months, Mark Mossler reported selling 19,519 shares for $76,680.39 on 08/12/2026 and 9,087 shares for $35,484.74 on 05/27/2026, in addition to the planned 15,000-share sale.

On which market is the planned CCCC share sale expected to occur?

The filing states that the planned sale of 15,000 CCCC shares is associated with trading on NASDAQ, with Morgan Stanley Smith Barney LLC Executive Financial Services named as the broker handling the transaction.

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

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

Add on Google Not now

Available on EDGAR 08/13/2026 - 04:18 PM Accepted by SEC EDGAR 08/13/2026 - 04:18 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	0001992219
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	C4 THERAPEUTICS, INC.
SEC File Number	001-39567
Address of Issuer	490 Arsenal Way, Suite 120 Watertown MASSACHUSETTS 02472
Phone	(617) 231-0700
Name of Person for Whose Account the Securities are To Be Sold	Mark Mossler
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	Officer

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	Morgan Stanley Smith Barney LLC Executive Financial Services 1 New York Plaza 8th Floor New York NY 10004	15000	61072.50	123025136	08/13/2026	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	08/13/2026	Stock Option Exercise	Issuer			15000	08/13/2026	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
Mark Mossler 490 Arsenal Way, Suite 120 Watertown MA 02472	Common	08/12/2026	19519	76680.39
Mark Mossler 490 Arsenal Way, Suite 120 Watertown MA 02472	Common	05/27/2026	9087	35484.74

144: Remarks and Signature

Remarks
Date of Notice	08/13/2026
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	/s/ Mark Mossler
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)