Beta Bionics officer to sell 4,375 shares

Beta Bionics officer Michael R. Mensinger filed a Rule 144 notice to sell 4,375 vested RSU shares mainly to cover tax obligations.

Rhea-AI Filing Summary

Beta Bionics, Inc. (BBNX) is the issuer of common stock for which officer Michael R. Mensinger has filed a notice under Rule 144 to sell shares.

The notice covers 4,375 shares of common stock, with an indicated aggregate market value of $84,940.63 as of September 2, 2026, to be sold through Morgan Stanley Smith Barney LLC on Nasdaq. The shares relate to restricted stock units that vested on September 1, 2026 and are described as compensation for services rendered to Beta Bionics. Mensinger also reports that during the prior three months he sold 4,378 shares of common stock on June 2, 2026 for proceeds of $55,193.88. The filing states that the current transaction is a sell-to-cover for taxes owed on recent stock unit vesting.

Key Figures

Planned shares to be sold: 4,375 shares Aggregate market value of planned sale: $84,940.63 Vesting date of RSUs: September 1, 2026 +3 more

6 metrics

Planned shares to be sold 4,375 shares Common stock covered by the Rule 144 notice

Aggregate market value of planned sale $84,940.63 Value for 4,375 shares as of September 2, 2026

Vesting date of RSUs September 1, 2026 Restricted Stock Units vesting under registered plan

Shares sold in prior 3 months 4,378 shares Common stock sold on June 2, 2026

Proceeds from prior sale $55,193.88 Aggregate sale price for 4,378 shares on June 2, 2026

Date of notice September 3, 2026 Date the Form 144 notice was signed

Key Terms

Rule 144, Restricted Stock Units, sell-to-cover, compensation for services rendered

4 terms

Rule 144 regulatory

"See the definition of "person" in paragraph (a) of Rule 144."

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.

Restricted Stock Units financial

"Restricted Stock Units vesting under registered plan"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

sell-to-cover financial

"This is a sell-to-cover transaction for taxes owed related to recent vesting"

Sell-to-cover is when part of newly issued or exercised company stock is immediately sold to pay required taxes and fees, so the recipient keeps the remaining shares. For investors this matters because it reduces the number of shares insiders or employees actually hold after a grant, can create small, routine share sales that aren’t signal of cashing out, and slightly increases share supply on the market—like selling a portion of a paycheck to cover the tax bill.

compensation for services rendered financial

"Compensation for services rendered to Issuer"

FAQ

What does the Form 144 filing disclose for BBNX?

The filing discloses that Michael R. Mensinger, an officer of Beta Bionics, filed a Rule 144 notice to sell 4,375 shares of common stock related to vested restricted stock units, primarily as a sell-to-cover transaction for tax obligations.

How many Beta Bionics (BBNX) shares are planned to be sold under this Form 144?

The notice covers a planned sale of 4,375 shares of Beta Bionics common stock, with an indicated aggregate market value of $84,940.63 as of September 2, 2026, to be sold through Morgan Stanley Smith Barney LLC on Nasdaq.

What is the source of the BBNX shares being sold by Michael R. Mensinger?

The shares arise from Restricted Stock Units that vested on September 1, 2026 under a registered plan and are described as compensation for services rendered to Beta Bionics. The transaction is noted as a sell-to-cover for tax obligations.

Has Michael R. Mensinger recently sold other Beta Bionics (BBNX) shares?

Yes. During the past three months, he reported selling 4,378 shares of Beta Bionics common stock on June 2, 2026, for aggregate proceeds of $55,193.88, as disclosed in the same Form 144 notice.

Which broker is handling the planned BBNX share sale under this Form 144?

The planned sale of 4,375 shares of Beta Bionics common stock is to be executed through Morgan Stanley Smith Barney LLC, located at 1 New York Plaza, New York, New York, with the shares listed for trading on Nasdaq.

What is the stated purpose of the BBNX share sale in this Form 144?

The remarks state that the transaction is a sell-to-cover for taxes owed related to the recent vesting of stock unit awards granted by Beta Bionics, indicating the sale is tied to RSU vesting rather than an ordinary discretionary sale.

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

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Available on EDGAR 09/03/2026 - 05:23 PM Accepted by SEC EDGAR 09/03/2026 - 05:19 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	0002048500
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	BETA BIONICS, INC.
SEC File Number	001-42491
Address of Issuer	11 HUGHES IRVINE CALIFORNIA 92618
Phone	949-427-7785
Name of Person for Whose Account the Securities are To Be Sold	Michael R. Mensinger
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 Stock	Morgan Stanley Smith Barney LLC 1 New York Plaza New York NY 10004	4375	84940.63	45123368	09/02/2026	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 Stock	09/01/2026	Restricted Stock Units vesting under registered plan	Issuer			4375	09/01/2026	Compensation for services rendered to Issuer

* 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
Michael Mensinger c/o Beta Bionics, Inc. 11 Hughes Irvine CA 92618	Common Stock	06/02/2026	4378	55193.88

144: Remarks and Signature

Remarks	This is a sell-to-cover transaction for taxes owed related to recent vesting of stock unit awards granted by the Issuer.
Date of Notice	09/03/2026
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/ Stephen Feider, Attorney-in-Fact
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)