Every Form 4 that MBX Biosciences, Inc. (MBX) has filed with the SEC in the last 12 months is listed below, newest first, and each one links through to the document itself with the summary and the scores our analysis gives it.
A Form 4 covers the transactions officers, directors and large holders report, so if you follow MBX and want that one kind of document rather than the whole filing history, this is the page to keep. The company's other filings, of every form, are on the full MBX filings page.
MBX Biosciences, Inc. reported that Chief Medical Officer Salomon Azoulay sold 370 shares of common stock on August 4, 2026 at a weighted average price of $65.77 per share to cover tax obligations from vesting restricted stock units under a mandatory sell-to-cover agreement, leaving 14,399 shares held directly.
Smither John W reported acquisition or exercise transactions in this Form 4 filing.
MBX Biosciences, Inc. Chief Financial Officer John W. Smither received two equity awards on August 3, 2026. He was granted 28,000 restricted stock units that vest 25% each July 13, 2027–2030, and a stock option for 130,000 shares at $64.41 per share, vesting 25% on July 13, 2027 and monthly thereafter over 36 months, all subject to continued service.
MBX Biosciences, Inc. reported equity awards to President and CEO Steven L. Hoerter on August 3, 2026. He received stock options for 331000.0000 shares of common stock at a $64.4100 exercise price, vesting 25% on July 13, 2027 and in 36 equal monthly installments thereafter, expiring August 3, 2036. He also received 71000.0000 restricted stock units vesting 25% annually each July 13 from 2027 through 2030. Following these grants he directly held 82938.0000 common shares, while 20000.0000 additional shares are held by the Steven L Hoerter Revocable Trust, with beneficial ownership disclaimed except for any pecuniary interest.
MBX Biosciences director Edward T. Mathers received a new stock option grant covering 12,500 shares of common stock. The option has an exercise price of $30.91 per share and expires on June 4, 2036. Following this grant, he holds 12,500 stock option rights directly.
The grant vests in full on the earlier of the one-year anniversary of the grant date or the date of the company’s next annual meeting of stockholders, as long as he continues serving as a non-employee director.
MBX Biosciences director Ora H. Pescovitz received a grant of stock options, reflecting equity-based compensation rather than an open-market trade. The award covers 12,500 options to buy common stock at an exercise price of $30.91 per share, expiring on June 4, 2036.
According to the terms, the grant will vest in full on the earlier of the one-year anniversary of the grant date or the company’s next annual stockholder meeting, subject to her continued service as a non-employee director. Following this filing, she also holds 24,329 shares of common stock directly.
MBX Biosciences, Inc. director and ten percent owner Patrick J. Heron received a grant of stock options covering 12,500 shares of common stock. The options have an exercise price of $30.91 per share and expire on June 4, 2036.
The grant will vest in full on the earlier of the one-year anniversary of the grant date or the date of the company’s next annual meeting of stockholders, as long as the non-employee director continues to provide services. This is a compensation-related award rather than an open-market share purchase or sale.
MBX Biosciences, Inc. director Laurie Stelzer received a grant of stock options covering 12,500 shares of common stock. The options have an exercise price of $30.91 per share and expire on June 4, 2036.
According to the terms, the grant will vest in full on the earlier of the one-year anniversary of the June 4, 2026 grant date or the date of the company’s next annual meeting of stockholders, as long as Stelzer continues to serve as a non-employee director. Following this award, Stelzer holds options for 12,500 shares directly.
MBX Biosciences director Steven L. Hoerter received a grant of stock options covering 12,500 shares of common stock. The options have an exercise price of $30.9100 per share and expire on June 4, 2036. According to the footnotes, the grant will vest in full on the earlier of the one-year anniversary of the grant date or the date of the company’s next annual meeting of stockholders, as long as he continues serving as a non-employee director.
After these transactions, Hoerter is reported as holding 11,938 shares of common stock directly and 20,000 shares indirectly through the Steven L Hoerter Revocable Trust dated November 2, 2018, where he serves as trustee and disclaims beneficial ownership except for any pecuniary interest.
MBX Biosciences director Steven Ryder received a grant of stock options covering 12,500 shares of common stock. The options have an exercise price of $30.91 per share and were awarded at no cost as a compensation grant.
The award vests in full on the earlier of the one-year anniversary of the grant date or the company’s next annual stockholder meeting, as long as Ryder continues serving as a non-employee director. After this grant, he holds options for 12,500 underlying shares, which expire on June 4, 2036.
MBX Biosciences, Inc. director Tiba Aynechi received a grant of stock options covering 12,500 shares of common stock as equity compensation. The options have an exercise price of $30.91 per share and expire on June 4, 2036. The grant will vest in full on the earlier of the one-year anniversary of the grant date or the company’s next annual meeting of stockholders, as long as the non-employee director continues to serve.
MBX Biosciences Chief Medical Officer Salomon Azoulay reported an exercise-and-sell transaction in company stock. On 2026-05-08, he exercised options to acquire a total of 70,003 shares of common stock at strike prices of $16.00 and $10.46 per share, then sold 70,003 shares in open-market transactions.
The sales occurred at weighted average prices of $38.30 and $38.38 per share, with individual trades executed between $35.00 and $41.26, under an approved Rule 10b5-1 trading plan adopted on January 27, 2026. Following these transactions, Azoulay directly holds 14,769 common shares.
He also retains stock options, including grants that had 30,008 and 194,540 options outstanding after the reported exercises, subject to vesting schedules that began vesting 25% on June 24, 2025 and September 12, 2025, with the remaining 75% vesting in 36 monthly installments.
MBX Biosciences Chief Medical Officer Salomon Azoulay reported a small routine sale of company stock. On May 6, 2026, Azoulay sold 231 shares of common stock in an open-market transaction at a weighted average price of $29.54 per share.
According to the disclosure, these shares were sold to cover tax obligations triggered by the vesting of restricted stock units under a mandatory sell-to-cover agreement with the company. After this transaction, Azoulay directly holds 14,769 shares of MBX Biosciences common stock, indicating this was a minor, tax-related disposition rather than a large change in ownership.
MBX Biosciences President & CEO P. Kent Hawryluk reported a small share sale primarily to cover taxes. On May 6, he sold 607 shares of common stock at a weighted average price of $29.54 per share to satisfy tax obligations tied to vesting restricted stock units under a mandatory sell-to-cover arrangement.
After this transaction, he directly holds 727,667 common shares and also has 486,777 shares held indirectly through the P. Kent Hawryluk Revocable Trust dated January 25, 2011. The filing notes that he disclaims beneficial ownership of the trust shares except to the extent of any pecuniary interest.
MBX Biosciences director Steven L. Hoerter reported new equity awards and existing holdings. He received a grant of 11,938 shares of Common Stock as restricted stock units, which will vest in full on November 6, 2026, subject to his continued service.
He was also granted stock options covering 74,249 shares of Common Stock at an exercise price of $29.78 per share, expiring on May 1, 2036. This option grant vests 50% on the grant date and the remaining 50% in equal monthly installments over six months, conditioned on continued service. Separately, 20,000 Common Stock shares are held indirectly through the Steven L Hoerter Revocable Trust, where he serves as trustee and disclaims beneficial ownership except for any pecuniary interest.
MBX Biosciences director Steven L. Hoerter received a stock option grant as part of his non-employee director compensation. The options have an exercise price of $27.08 per share and expire on November 21, 2035. The grant vests in equal monthly installments over one year from November 6, 2025, and was adjusted so his 2025 equity compensation does not exceed $1,000,000 in aggregate grant date fair value under the company’s director compensation policy.
MBX Biosciences, Inc. reported that director Steven L. Hoerter received a grant of stock options covering 33,751 shares of common stock. The options have an exercise price of $24.74 per share and were awarded as part of the company’s Non-Employee Director Compensation Policy.
The footnotes state that these grants were adjusted so the director’s total 2025 equity compensation does not exceed $1,000,000 based on grant date fair value under FASB Topic ASC 718. The grant vests in equal monthly installments over one year, contingent on his continued service to the company.
MBX Biosciences, Inc. President & CEO P. Kent Hawryluk reported an open-market purchase of 18,500 shares of Common Stock on March 13, 2026, at a weighted average price of $28.4142 per share.
The shares were bought through the P. Kent Hawryluk Revocable Trust, with prices ranging from $28.28 to $28.48 per share. Following this transaction, the trust holds 486,777 shares indirectly, and his direct holdings are reported at 728,274 shares. The filing notes that he disclaims beneficial ownership of the trust shares except for any pecuniary interest.
MBX Biosciences, Inc. director and President & CEO P. Kent Hawryluk reported exercising stock options into common stock. On February 26, 2026, he exercised options covering 28,768 shares, with the resulting common stock recorded at $16.00 per share.
After these transactions, his directly held common stock position is 728,274 shares, and directly held stock options total 91,668 shares underlying options. An additional 468,277 common shares are held indirectly by the P. Kent Hawryluk Revocable Trust, where he serves as trustee and disclaims beneficial ownership except for any pecuniary interest.
MBX Biosciences Chief Medical Officer Azoulay Salomon reported new equity compensation. On February 2, 2026, Salomon received 15,000 shares of common stock, representing a grant of restricted stock units that vest over four years in equal quarterly installments, conditioned on continued service.
On the same date, Salomon was also granted a stock option for 70,000 shares of common stock with an exercise price of $39.07 per share. These options vest and become exercisable in 48 equal monthly installments beginning on March 2, 2026, also subject to continued service. Following these grants, Salomon beneficially owns 15,000 common shares and 70,000 derivative securities directly.
MBX Biosciences, Inc.’s Chief Financial Officer Richard Bartram received new equity awards in the form of restricted stock units and stock options. On February 2, 2026, he was granted 15,000 shares of common stock as RSUs at a price of $0 per share, all held directly after the grant.
He was also granted a stock option to buy 70,000 shares of common stock with an exercise price of $39.07 per share. These options vest and become exercisable in 48 equal monthly installments beginning on March 2, 2026, while the 15,000 RSUs vest in equal quarterly installments over four years. All vesting is conditioned on his continued service with the company.
MBX Biosciences President & CEO P. Kent Hawryluk reported new equity awards. On February 2, 2026, he received 35,250 shares of common stock in the form of restricted stock units at $0 per share, bringing his directly held common stock to 699,506 shares.
He was also granted a stock option to buy 164,500 shares of common stock at an exercise price of $39.07 per share, expiring on February 2, 2036, vesting in 48 equal monthly installments starting March 2, 2026. In addition, 468,277 shares are held indirectly by the P. Kent Hawryluk Revocable Trust, for which he serves as trustee.
MBX Biosciences granted director Laurie Stelzer stock options covering 32,000 shares of common stock on January 20, 2026. These options have an exercise price of $43.14 per share and are held as a direct ownership position.
One-third of the underlying shares will vest and become exercisable on January 20, 2027, the first anniversary of the grant date, with the remaining two-thirds vesting monthly over the following two years, subject to her continued service. After this grant, she beneficially owns 32,000 derivative securities linked to MBX Biosciences common stock.
MBX Biosciences, Inc. (MBX) disclosed a new equity award to a director. On 11/22/2025, the director received a stock option to purchase 8,000 shares of common stock at an exercise price of $27.08 per share, reported as a derivative security in Table II.
The option covers 8,000 underlying shares of common stock and is held directly by the reporting person. According to the footnote, the grant will vest in equal monthly installments over a one-year period from November 6, 2025, conditioned on the non-employee director continuing to provide services to the company.
MBX Biosciences (MBX) reported a director stock option grant. On November 6, 2025, the director received 100,000 stock options with an exercise price of $24.74. The options vest in equal monthly installments over one year from the grant date, contingent on continued service. The award expires on November 5, 2035. Following the grant, the reporting person held 100,000 derivative securities, reported as Direct (D) ownership.
MBX Biosciences (MBX) reported an insider transaction by its President & CEO and Director on 10/24/2025. The executive exercised a stock option (Code M) to acquire 182,859 shares of common stock at an exercise price of $3.25 per share. Following the transaction, beneficial ownership stood at 664,256 shares held directly and 468,277 shares held indirectly through a revocable trust. The filing lists 129,708 derivative securities (options) remaining post-transaction. The option began vesting monthly from 11/07/2022 and is scheduled to fully vest by 11/07/2026, with early-exercise permitted subject to an issuer repurchase right.
MBX Biosciences (MBX) reported an insider share purchase by its President & CEO and Director on 10/20/2025. The reporting person bought 20,000 shares of common stock at a weighted average price of $13.6395, with trades executed between $13.60 and $13.6399.
Following the transaction, the filing lists 481,397 shares as directly owned and 468,277 shares as indirectly owned by a trust. The trust is identified as the P. Kent Hawryluk Revocable Trust, with the reporting person serving as trustee.
MBX Biosciences (MBX) reported an insider purchase by a director. On 10/17/2025, a revocable trust of the reporting person acquired 20,000 shares of common stock at $13.2492 per share (Transaction Code P). Following the transaction, 20,000 shares were beneficially owned indirectly by the trust. The filer notes a disclaimer of beneficial ownership beyond any pecuniary interest, as stated in the footnote.
MBX Biosciences Form 4 summary: On 09/26/2025 an affiliated investor group acquired 666,666 shares of MBX common stock at $18.00 per share. After the reported purchase the group beneficially owned 5,219,440 shares. The shares are held of record by Frazier Life Sciences X, L.P., with FHMLS X, L.P., FHMLS X, L.L.C., James N. Topper and Patrick J. Heron having shared voting and investment power; Heron is identified as a reporting person and a director and 10% owner. The filing is signed by an attorney-in-fact on behalf of the reporting parties.