MASS shareholder plans sale of 100,000 shares

Christopher Brown filed a Form 144 indicating an intention to sell 100,000 shares of MASS common stock, originally acquired as founders shares, through Morgan Stanley Smith Barney LLC’s Executive Financial Services.

Rhea-AI Filing Summary

Christopher Brown filed a Form 144 indicating an intention to sell 100,000 shares of MASS common stock, originally acquired as founders shares, through Morgan Stanley Smith Barney LLC’s Executive Financial Services. The filing lists 37,813,621 MASS common shares outstanding and places the proposed sale value at $888,000.00, with prior sales in recent months executed under a Rule 10b5-1 trading plan.

Key Figures

Proposed shares to be sold: 100000 shares Proposed sale value: 888000.00 Shares outstanding: 37813621 shares +3 more

6 metrics

Proposed shares to be sold 100000 shares Common stock indicated on Form 144 as proposed for sale

Proposed sale value 888000.00 Approximate aggregate market value of 100,000 shares

Shares outstanding 37813621 shares Total MASS common shares outstanding referenced in the filing

Sale on 05/28/2026 30000 shares for 270000.00 10b5-1 common stock sale by Christopher Brown

Sale on 08/05/2026 20000 shares for 169798.00 10b5-1 common stock sale by Christopher Brown

Founders shares acquired 100000 shares Founders shares dated 02/10/2012 listed as issuer-originated

Key Terms

Form 144, 10b5-1 Sales, Founders Shares, Executive Financial Services

4 terms

Form 144 regulatory

"Filer Information | | | 144: Filer Information"

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.

10b5-1 Sales regulatory

"10b5-1 Sales for CHRISTOPHER BROWN 44 Third Avenue Burlington"

10b5-1 sales are pre-arranged stock-trading plans that let company insiders automatically buy or sell shares according to a fixed schedule or formula, even if they later learn confidential information. Think of it as setting up an automatic thermostat for trades: it creates a clear, documented path that can protect insiders from insider-trading accusations and gives investors a signal about predictable insider activity—though it can also simply be a way for insiders to diversify or raise cash.

Founders Shares financial

"Common | 02/10/2012 | Founders Shares | Issuer"

Founders shares are a special block of a company’s stock originally given to the people who started the business; they often carry extra voting power or favorable terms compared with regular shares. For investors, these shares matter because they concentrate control and influence how future funding, ownership dilution, and decision-making will play out—think of founders shares as the steering wheel that can steer a company’s direction even as more passengers (investors) climb aboard.

Executive Financial Services financial

"Morgan Stanley Smith Barney LLC Executive Financial Services 1 New York"

FAQ

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

What does the MASS Form 144 filed by Christopher Brown disclose?

The Form 144 discloses that Christopher Brown plans to sell 100,000 MASS common shares, valued at about $888,000.00, originally acquired as founders shares, through Morgan Stanley Smith Barney LLC.

How many MASS shares has Christopher Brown already sold recently?

The filing lists several prior sales, including 30,000 shares for $270,000.00 on 05/28/2026 and other transactions such as 20,000 shares for $176,774.00 on 07/01/2026, all under a 10b5-1 plan.

What is the total number of MASS shares outstanding mentioned in the Form 144?

The document states that there are 37,813,621 MASS common shares outstanding. This figure provides context for the 100,000 shares Brown expects to sell under the Form 144 notice.

Is Christopher Brown’s MASS stock sale under a Rule 10b5-1 trading plan?

Yes. The recent sales disclosed for Christopher Brown are labeled as 10b5-1 sales, indicating that transactions, such as the 20,000-share sale on 08/05/2026, were executed under a pre-arranged Rule 10b5-1 trading plan.

What type of MASS shares is Christopher Brown planning to sell?

The planned sale covers 100,000 shares of MASS common stock identified as founders shares. These are to be sold through Morgan Stanley Smith Barney LLC’s Executive Financial Services at an indicated value of $888,000.00.

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

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Available on EDGAR 08/10/2026 - 04:38 PM Accepted by SEC EDGAR 08/10/2026 - 04:37 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	0001836988
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	908 DEVICES INC
SEC File Number	001-39815
Address of Issuer	44 Third Avenue Burlington MASSACHUSETTS 01803
Phone	8572541500
Name of Person for Whose Account the Securities are To Be Sold	CHRISTOPHER BROWN
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	Director

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	100000	888000.00	37813621	08/10/2026	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	02/10/2012	Founders Shares	Issuer			100000	02/10/2012	N/A

* 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
10b5-1 Sales for CHRISTOPHER BROWN 44 Third Avenue Burlington MA 01803	Common	08/05/2026	20000	169798.00
10b5-1 Sales for CHRISTOPHER BROWN 44 Third Avenue Burlington MA 01803	Common	07/02/2026	2200	19841.58
10b5-1 Sales for CHRISTOPHER BROWN 44 Third Avenue Burlington MA 01803	Common	07/01/2026	20000	176774.00
10b5-1 Sales for CHRISTOPHER BROWN 44 Third Avenue Burlington MA 01803	Common	06/23/2026	9900	89488.08
10b5-1 Sales for CHRISTOPHER BROWN 44 Third Avenue Burlington MA 01803	Common	06/04/2026	100	900.00
10b5-1 Sales for CHRISTOPHER BROWN 44 Third Avenue Burlington MA 01803	Common	06/03/2026	20000	174532.00
10b5-1 Sales for CHRISTOPHER BROWN 44 Third Avenue Burlington MA 01803	Common	05/28/2026	30000	270000.00

144: Remarks and Signature

Remarks
Date of Notice	08/10/2026
Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1	11/24/2025
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	/s/ CHRISTOPHER BROWN
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)