MBIO

SEC source: 0001104659-26-049430 · tm2612756-1_4seq1.xml · nonDerivative · entry 1

Litchman Manuel MD · CIK 0001709485 · Director · President, CEO and Interim CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,615

F1 · shares: 19 shares of common stock were relinquished to cover tax liability associated with the delivery of shares of common stock upon the vesting of restricted stock units.

SEC source: 0001429260-26-000002 · form4-01052026_040122.xml · nonDerivative · entry 1

Fortress Biotech, Inc. · CIK 0001429260 · 10% owner

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 536,577

F1 · shares: The Reporting Person is entitled to an annual dividend on its Class A Preferred Stock equal to 2.5% of the Issuer's fully diluted outstanding capitalization on December 31. 278,385 shares were granted by the Issuer to the Reporting person for the 2025 annual dividend.

SEC source: 0001104659-25-125233 · tm2534509-3_4seq1.xml · nonDerivative · entry 1

Herskowitz Neil · CIK 0001298246 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 145

F1 · shares: Represents a private sale of 247 shares of common stock to another member of the board of directors of the Issuer.

F2 · balance_after: Effective January 15, 2025, the Issuer effected a one-for-fifty reverse stock split of its common stock (the "Reverse Stock Split"). The amount of common stock reflected on this Form 4 has been adjusted to reflect the Reverse Stock Split.

SEC source: 0001104659-25-125232 · tm2534509-2_4seq1.xml · nonDerivative · entry 1

Chill Adam J. · CIK 0001626451 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 375

F1 · balance_after: Effective January 15, 2025, the Issuer effected a one-for-fifty reverse stock split of its common stock (the "Reverse Stock Split"). The amount of common stock reflected on this Form 4 has been adjusted to reflect the Reverse Stock Split.

SEC source: 0001104659-25-125227 · tm2534509-1_4seq1.xml · nonDerivative · entry 1

Jin David · CIK 0001930732 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 286

F1 · shares: Represents a private purchase of 247 shares of common stock from another member of the board of directors of the Issuer.

F2 · balance_after: Effective January 15, 2025, the Issuer effected a one-for-fifty reverse stock split of its common stock (the "Reverse Stock Split"). The amount of common stock reflected on this Form 4 has been adjusted to reflect the Reverse Stock Split.

SEC source: 0001429260-25-000004 · form4-10012025_041032.xml · nonDerivative · entry 1

Fortress Biotech, Inc. · CIK 0001429260 · 10% owner

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 258,192

F1 · shares: The Issuer is required to grant to the Reporting Person an equity fee in shares of the Issuer's Common Stock equal to 2.5% of the gross amount of any debt or equity financing consummated by the Issuer. These shares were granted by the Issuer to the Reporting Person following the receipt of proceeds by the Issuer upon the exercise of warrants previously issued by the Issuer.

SEC source: 0001104659-25-040237 · tm2513385-1_4seq1.xml · nonDerivative · entry 1

Litchman Manuel MD · CIK 0001709485 · Director · President, CEO and Interim CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,634

F1 · shares: 27 shares of common stock were relinquished to cover tax liability associated with the delivery of shares of common stock upon the vesting of restricted stock units.

F2 · balance_after: Effective January 15, 2025, the Issuer effected a one-for-fifty reverse stock split of its common stock (the "Reverse Stock Split"). The amount of common stock reflected on this Form 4 has been adjusted to reflect the Reverse Stock Split.

SEC source: 0001415889-25-009620 · form4-04022025_040407.xml · nonDerivative · entry 1

Fortress Biotech, Inc. · CIK 0001429260 · 10% owner

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 198,858

F1 · shares: The Issuer is required to grant to the Reporting Person an equity fee in shares of the Issuer's Common Stock equal to 2.5% of the gross amount of any debt or equity financing consummated by the Issuer. These shares were granted by the Issuer to the Reporting Person following the receipt of proceeds by the Issuer upon the exercise of warrants previously issued by the Issuer.

SEC source: 0001104659-24-076298 · tm2418561-1_4seq1.xml · nonDerivative · entry 1

Fortress Biotech, Inc. · CIK 0001429260 · 10% owner

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 2,502,991

F1 · shares: The Issuer is required to grant to the Reporting Person an equity fee in shares of the Issuer's Common Stock equal to 2.5% of the gross amount of any debt or equity financing consummated by the Issuer. 575,191 shares were granted by the Issuer to the Reporting Person following the closing of equity financings.

F1 · balance_after: The Issuer is required to grant to the Reporting Person an equity fee in shares of the Issuer's Common Stock equal to 2.5% of the gross amount of any debt or equity financing consummated by the Issuer. 575,191 shares were granted by the Issuer to the Reporting Person following the closing of equity financings.

SEC source: 0001104659-24-068411 · tm2416466-2_4seq1.xml · nonDerivative · entry 1

Litchman Manuel MD · CIK 0001709485 · Director · President and CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 83,024

F1 · shares: 1,396 shares of common stock were relinquished to cover tax liability associated with the delivery of shares of common stock upon the vesting of restricted stock units.

F2 · balance_after: Includes 5,000 shares of common stock acquired under the Mustang Bio, Inc. Employee Stock Purchase Plan on March 1, 2024.

SEC source: 0001104659-24-000859 · tm241755-3_4seq1.xml · nonDerivative · entry 1

Fortress Biotech, Inc. · CIK 0001429260 · 10% owner

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,927,800

F1 · shares: Effective April 3, 2023, the Issuer effected a one-for-fifteen reverse stock split of its common stock (the "Reverse Split"). The amount of common stock reflected on this Form 4 has been adjusted to reflect the Reverse Split.

F2 · shares: The Issuer is required to grant to the Reporting Person an equity fee in shares of the Issuer's Common Stock equal to 2.5% of the gross amount of any debt or equity financing consummated by the Issuer. 66,003 shares were granted by the Issuer to the Reporting Person following the closing of equity financings.

F3 · shares: The Reporting Person is entitled to an annual dividend on its Class A Preferred Stock equal to 2.5% of the Issuer's fully diluted outstanding capitalization on December 31. 353,089 shares were granted by the Issuer to the Reporting Person for the 2023 annual dividend.

F1 · balance_after: Effective April 3, 2023, the Issuer effected a one-for-fifteen reverse stock split of its common stock (the "Reverse Split"). The amount of common stock reflected on this Form 4 has been adjusted to reflect the Reverse Split.

SEC source: 0001104659-23-079114 · tm2320790-4_4seq1.xml · nonDerivative · entry 1

ROSENWALD LINDSAY A MD · CIK 0000941841 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 60,525

F1 · shares: The Reporting Person was granted 7,246 restricted shares pursuant to the Issuer's 2016 Incentive Plan on July 5, 2023. The shares will vest on July 5, 2026, subject to the Reporting Person's continued service on the Issuer's board on such date.

F2 · shares: Effective April 3, 2023, the Issuer effected a fifteen-for-one reverse stock split of its common stock (the "Reverse Stock Split"). The amount of common stock reflected on this Form 4 has been adjusted to reflect the Reverse Stock Split.

F2 · balance_after: Effective April 3, 2023, the Issuer effected a fifteen-for-one reverse stock split of its common stock (the "Reverse Stock Split"). The amount of common stock reflected on this Form 4 has been adjusted to reflect the Reverse Stock Split.

F3 · balance_after: Includes restricted share units, which vest over various time periods.

SEC source: 0001104659-23-079112 · tm2320790-3_4seq1.xml · nonDerivative · entry 1

WEISS MICHAEL S · CIK 0001038977 · Director

10b5-1 filing: No plan indicated

Ownership: Indirect · See Footnote

Disclosed balance after: 49,637

F1 · shares: The Reporting Person was granted 7,246 restricted shares pursuant to the Issuer's 2016 Incentive Plan on July 5, 2023. The shares will vest on July 5, 2026, subject to the Reporting Person's continued service on the Issuer's board on such date.

F2 · shares: Effective April 3, 2023, the Issuer effected a fifteen-for-one reverse stock split of its common stock (the "Reverse Stock Split"). The amount of common stock reflected on this Form 4 has been adjusted to reflect the Reverse Stock Split.

F2 · balance_after: Effective April 3, 2023, the Issuer effected a fifteen-for-one reverse stock split of its common stock (the "Reverse Stock Split"). The amount of common stock reflected on this Form 4 has been adjusted to reflect the Reverse Stock Split.

F3 · balance_after: Includes restricted share units, which vest over various time periods.

F4 · ownership.nature: The shares are held by Caribe BioAdvisors, LLC, of which Mr. Weiss is the sole member.

SEC source: 0001104659-23-079111 · tm2320790-2_4seq1.xml · nonDerivative · entry 1

Herskowitz Neil · CIK 0001298246 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 19,703

F1 · shares: The Reporting Person was granted 7,246 restricted shares pursuant to the Issuer's 2016 Incentive Plan on July 5, 2023. The shares will vest on July 5, 2026, subject to the Reporting Person's continued service on the Issuer's board on such date.

F2 · shares: Effective April 3, 2023, the Issuer effected a fifteen-for-one reverse stock split of its common stock (the "Reverse Stock Split"). The amount of common stock reflected on this Form 4 has been adjusted to reflect the Reverse Stock Split.

F2 · balance_after: Effective April 3, 2023, the Issuer effected a fifteen-for-one reverse stock split of its common stock (the "Reverse Stock Split"). The amount of common stock reflected on this Form 4 has been adjusted to reflect the Reverse Stock Split.

F3 · balance_after: Includes restricted share units, which vest over various time periods.

SEC source: 0001104659-23-079118 · tm2320790-6_4seq1.xml · nonDerivative · entry 1

ZELEFSKY MICHAEL J · CIK 0001266801 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 18,970

F1 · shares: The Reporting Person was granted 7,246 restricted shares pursuant to the Issuer's 2016 Incentive Plan on July 5, 2023. The shares will vest on July 5, 2026, subject to the Reporting Person's continued service on the Issuer's board on such date.

F2 · shares: Effective April 3, 2023, the Issuer effected a fifteen-for-one reverse stock split of its common stock (the "Reverse Stock Split"). The amount of common stock reflected on this Form 4 has been adjusted to reflect the Reverse Stock Split.

F2 · balance_after: Effective April 3, 2023, the Issuer effected a fifteen-for-one reverse stock split of its common stock (the "Reverse Stock Split"). The amount of common stock reflected on this Form 4 has been adjusted to reflect the Reverse Stock Split.

F3 · balance_after: Includes restricted share units, which vest over various time periods.

SEC source: 0001104659-23-079117 · tm2320790-5_4seq1.xml · nonDerivative · entry 1

Chill Adam J. · CIK 0001626451 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 19,170

F1 · shares: The Reporting Person was granted 7,246 restricted shares pursuant to the Issuer's 2016 Incentive Plan on July 5, 2023. The shares will vest on July 5, 2026, subject to the Reporting Person's continued service on the Issuer's board on such date.

F2 · shares: Effective April 3, 2023, the Issuer effected a fifteen-for-one reverse stock split of its common stock (the "Reverse Stock Split"). The amount of common stock reflected on this Form 4 has been adjusted to reflect the Reverse Stock Split.

F2 · balance_after: Effective April 3, 2023, the Issuer effected a fifteen-for-one reverse stock split of its common stock (the "Reverse Stock Split"). The amount of common stock reflected on this Form 4 has been adjusted to reflect the Reverse Stock Split.

F3 · balance_after: Includes restricted share units, which vest over various time periods.

SEC source: 0001104659-23-079110 · tm2320790-1_4seq1.xml · nonDerivative · entry 1

Litchman Manuel MD · CIK 0001709485 · Director · President and CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 111,079

F1 · shares: Represents an award of 5,000 restricted stock units that will vest in four annual installments after the grant date, vesting in full on April 24, 2027.

F2 · shares: Effective April 3, 2023, the Issuer effected a fifteen-for-one reverse stock split of its common stock (the "Reverse Stock Split"). The amount of common stock reflected on this Form 4 has been adjusted to reflect the Reverse Stock Split.

F2 · balance_after: Effective April 3, 2023, the Issuer effected a fifteen-for-one reverse stock split of its common stock (the "Reverse Stock Split"). The amount of common stock reflected on this Form 4 has been adjusted to reflect the Reverse Stock Split.

F3 · balance_after: Includes restricted share units, which vest over various time periods.

SEC source: 0001104659-24-068409 · tm2416466-1_4seq1.xml · nonDerivative · entry 2

Litchman Manuel MD · CIK 0001709485 · Director · President and CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 79,420

F3 · shares: 1,572 shares of common stock were relinquished to cover tax liability associated with the delivery of shares of common stock upon the vesting of restricted stock units.

SEC source: 0001104659-23-001929 · tm232514-1_4seq1.xml · nonDerivative · entry 1

Fortress Biotech, Inc. · CIK 0001429260 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 22,630,620

F1 · shares: The Reporting Person is entitled to an annual dividend on its Class A Preferred Stock equal to 2.5% of the Issuer's fully diluted outstanding capitalization on December 31. These shares were granted by the Issuer to the Reporting Person for the 2022 annual dividend.

F2 · balance_after: The total number of shares beneficially owned by the Reporting Person includes those transactions as disclosed on the table filed herewith as Exhibit 99.

SEC source: 0001104659-23-040932 · tm2311237-5_4seq1.xml · nonDerivative · entry 3

ROSENWALD LINDSAY A MD · CIK 0000941841 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 299,181

F1 · shares: Shares acquired as purchases made under the Issuer's Employee Stock Purchase Plan ("ESPP") during the ESPP offering period.

F2 · balance_after: Includes restricted share units, which vest over various time periods.

SEC source: 0001104659-23-040934 · tm2311237d6_4seq1.xml · nonDerivative · entry 3

Litchman Manuel MD · CIK 0001709485 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,098,987

F1 · shares: Shares acquired as purchases made under the Issuer's Employee Stock Purchase Plan ("ESPP") during the ESPP offering period.

F2 · balance_after: Includes restricted share units, which vest over various time periods.

SEC source: 0001104659-23-040932 · tm2311237-5_4seq1.xml · nonDerivative · entry 2

ROSENWALD LINDSAY A MD · CIK 0000941841 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 294,181

F3 · shares: The Reporting Person was granted 71,664 restricted shares pursuant to the Issuer's 2016 Incentive Plan on July 29, 2022. The shares will vest on June 17, 2025, subject to the Reporting Person's continued service on the Issuer's board on such date.

F2 · balance_after: Includes restricted share units, which vest over various time periods.

SEC source: 0001104659-23-040923 · tm2311237d1_4seq1.xml · nonDerivative · entry 1

WEISS MICHAEL S · CIK 0001038977 · Director

10b5-1 filing: No plan indicated

Ownership: Indirect · See Note 3

Disclosed balance after: 135,861

F1 · shares: The Reporting Person was granted 71,664 restricted shares pursuant to the Issuer's 2016 Incentive Plan on July 29, 2022. The shares will vest on June 17, 2025, subject to the Reporting Person's continued service on the Issuer's board on such date.

F2 · balance_after: Includes restricted share units, which vest over various time periods.

F3 · ownership.nature: The shares are held by Caribe BioAdvisors, LLC, of which Mr. Weiss is the sole member.

SEC source: 0001104659-23-040929 · tm2311237-4_4seq1.xml · nonDerivative · entry 1

Herskowitz Neil · CIK 0001298246 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 186,861

F1 · shares: The Reporting Person was granted 71,664 restricted shares pursuant to the Issuer's 2016 Incentive Plan on July 29, 2022. The shares will vest on June 17, 2025, subject to the Reporting Person's continued service on the Issuer's board on such date.

F2 · balance_after: Includes restricted share units, which vest over various time periods.

SEC source: 0001104659-23-040927 · tm2311237d3_4seq1.xml · nonDerivative · entry 1

ZELEFSKY MICHAEL J · CIK 0001266801 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 175,861

F1 · shares: The Reporting Person was granted 71,664 restricted shares pursuant to the Issuer's 2016 Incentive Plan on July 29, 2022. The shares will vest on June 17, 2025, subject to the Reporting Person's continued service on the Issuer's board on such date.

F2 · balance_after: Includes restricted share units, which vest over various time periods.

SEC source: 0001104659-23-040924 · tm2311237-2_4seq1.xml · nonDerivative · entry 1

Chill Adam J. · CIK 0001626451 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 178,861

F1 · shares: The Reporting Person was granted 71,664 restricted shares pursuant to the Issuer's 2016 Incentive Plan on July 29, 2022. The shares will vest on June 17, 2025, subject to the Reporting Person's continued service on the Issuer's board on such date.

F2 · balance_after: Includes restricted share units, which vest over various time periods.

SEC source: 0001104659-23-040934 · tm2311237d6_4seq1.xml · nonDerivative · entry 2

Litchman Manuel MD · CIK 0001709485 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,093,987

F3 · shares: Represents an award of 61,000 restricted stock units that will vest in four annual installments after the grant date, vesting in full on April 24, 2026.

F2 · balance_after: Includes restricted share units, which vest over various time periods.

SEC source: 0001104659-24-068409 · tm2416466-1_4seq1.xml · nonDerivative · entry 1

Litchman Manuel MD · CIK 0001709485 · Director · President and CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 80,992

F1 · shares: 1,248 shares of common stock were relinquished to cover tax liability associated with the delivery of shares of common stock upon the vesting of restricted stock units.

F2 · balance_after: The amount of common stock reflected on this Form 4 has been adjusted to reflect a 1-for-15 reverse stock split that occurred subsequent to this transaction.

F4 · balance_after: Includes 3,975 shares of common stock acquired under the Mustang Bio, Inc. Employee Stock Purchase Plan on March 1, 2023 and September 1, 2023.

SEC source: 0001104659-23-040932 · tm2311237-5_4seq1.xml · nonDerivative · entry 1

ROSENWALD LINDSAY A MD · CIK 0000941841 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 222,517

F1 · shares: Shares acquired as purchases made under the Issuer's Employee Stock Purchase Plan ("ESPP") during the ESPP offering period.

F2 · balance_after: Includes restricted share units, which vest over various time periods.

SEC source: 0001104659-23-040934 · tm2311237d6_4seq1.xml · nonDerivative · entry 1

Litchman Manuel MD · CIK 0001709485 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,032,987

F1 · shares: Shares acquired as purchases made under the Issuer's Employee Stock Purchase Plan ("ESPP") during the ESPP offering period.

F2 · balance_after: Includes restricted share units, which vest over various time periods.

SEC source: 0001104659-21-150544 · tm2135704d1_4.xml · nonDerivative · entry 2

Achenbach Brian · CIK 0001760132 · SVP, Fin. & Corp. Controller

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 144,729

F2 · kind: 4,374 shares were sold in connection with the vesting of 13,750 shares on December 4, 2021, these shares were sold by the Company's restricted stock administrator in order to satisfy Mr. Achenbach's tax withholding obligations. Mr. Achenbach had no discretion with respect to such sale, which was transacted automatically in accordance with the Company's corporate policies regarding the vesting of restricted stock.

F3 · price: Represents the weighted average sales price.

F4 · balance_after: Includes restricted share units, which vest over various time periods.

SEC source: 0001104659-21-150544 · tm2135704d1_4.xml · nonDerivative · entry 1

Achenbach Brian · CIK 0001760132 · SVP, Fin. & Corp. Controller

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 149,103

F1 · shares: Each restricted stock unit represents the right to receive one share of Common Stock of Mustang Bio, Inc. The restricted stock units will vest at different times over a period of 4 years.

F4 · balance_after: Includes restricted share units, which vest over various time periods.

SEC source: 0001104659-21-135706 · tm2132286-1_4seq1.xml · nonDerivative · entry 1

Litchman Manuel MD · CIK 0001709485 · Director · President and CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 1,027,987

F1 · price: Reflects the weighted average purchase price of multiple same-way open market purchase transactions effected by the Reporting Person on the same day at different prices through a purchase order executed by a broker-dealer. The Reporting Person reported on a single line all such transactions that occurred within a one-dollar price range. The range of prices for the purchase transactions on October 27, 2021, was $2.22 to $2.26. The Reporting Person hereby undertakes to provide upon request by the Securities Exchange Commission staff, the Issuer, or a shareholder of the Issuer, full information regarding the number of shares purchased at each separate price.

F2 · balance_after: Includes restricted stock units, which vest over various time periods.

SEC source: 0001104659-21-128486 · tm2130779-1_4seq1.xml · nonDerivative · entry 1

Achenbach Brian · CIK 0001760132 · SVP, Fin. & Corp. Controller

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 126,603

F1 · kind: 4,450 shares were sold in connection with the vesting of 14,688 shares on October 10, 2021, these shares were sold by the Company's restricted stock administrator in order to satisfy Mr. Achenbach's tax withholding obligations. Mr. Achenbach had no discretion with respect to such sale, which was transacted automatically in accordance with the Company's corporate policies regarding the vesting of restricted stock.

F2 · price: Represents the weighted average sales price.

F3 · balance_after: Includes restricted share units, which vest over various time periods.

SEC source: 0001104659-21-119389 · tm2128458-2_4seq1.xml · nonDerivative · entry 1

ROSENWALD LINDSAY A MD · CIK 0000941841 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 218,423

F1 · shares: These shares were acquired under the Mustang Bio, Inc. Employee Share Purchase Plan ("ESPP") for the ESPP purchase period beginning on March 1, 2021 and ending on August 31, 2021 in transactions that were exempt under both Rule 16b-3(d) and Rule 16b-3(c). In accordance with the terms of the ESPP, these shares were purchased at a price equal to 85% of the fair market value closing price of the Issuer's ordinary shares on August 31, 2021 (the purchase date of the offering period).

F2 · balance_after: Includes restricted shares, which vest over various time periods.

SEC source: 0001104659-21-119384 · tm2128458-1_4seq1.xml · nonDerivative · entry 1

Litchman Manuel MD · CIK 0001709485 · Director · President and CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 962,987

F1 · shares: These shares were acquired under the Mustang Bio, Inc. Employee Share Purchase Plan ("ESPP") for the ESPP purchase period beginning on March 1, 2021 and ending on August 31, 2021 in transactions that were exempt under both Rule 16b-3(d) and Rule 16b-3(c). In accordance with the terms of the ESPP, these shares were purchased at a price equal to 85% of the fair market value closing price of the Issuer's ordinary shares on August 31, 2021 (the purchase date of the offering period).

F2 · balance_after: Includes restricted stock units, which vest over various time periods.

SEC source: 0001104659-21-100783 · tm2124277-1_4seq1.xml · nonDerivative · entry 1

Litchman Manuel MD · CIK 0001709485 · Director · President and CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 960,241

F1 · price: Reflects the weighted average purchase price of multiple same-way open market purchase transactions effected by the Reporting Person on the same day at different prices through a purchase order executed by a broker-dealer. The Reporting Person reported on a single line all such transactions that occurred within a one-dollar price range. The range of prices for the purchase transactions on July 30, 2021, was $2.89 to $2.94. The Reporting Person hereby undertakes to provide upon request by the Securities Exchange Commission staff, the Issuer, or a shareholder of the Issuer, full information regarding the number of shares purchased at each separate price.

F2 · balance_after: Includes restricted stock units, which vest over various time periods.

SEC source: 0001104659-21-090243 · tm2121675-4_4seq1.xml · nonDerivative · entry 1

ROSENWALD LINDSAY A MD · CIK 0000941841 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 217,253

F1 · shares: The Reporting Person was granted 13,774 restricted shares pursuant to the Issuer's 2016 Incentive Plan on June 28, 2021. The shares will vest on June 17, 2024, subject to the Reporting Person's continued service on the Issuer's board on such date.

F2 · balance_after: Includes restricted share units, which vest over various time periods.

SEC source: 0001104659-21-090246 · tm2121675-5_4seq1.xml · nonDerivative · entry 1

WEISS MICHAEL S · CIK 0001038977 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Note 3

Disclosed balance after: 64,197

F1 · shares: 13,774 restricted shares were granted pursuant to the Issuer's 2016 Incentive Plan on June 28, 2021. The shares will vest on June 17, 2024, subject to the Reporting Person's continued service on the Issuer's board on such date.

F2 · balance_after: Includes restricted share units, which vest over various time periods.

F3 · ownership.nature: The shares are held by Caribe BioAdvisors, LLC, of which Mr. Weiss is the sole member.

SEC source: 0001104659-21-090240 · tm2121675-2_4seq1.xml · nonDerivative · entry 1

Herskowitz Neil · CIK 0001298246 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 115,197

F1 · shares: The Reporting Person was granted 13,774 restricted shares pursuant to the Issuer's 2016 Incentive Plan on June 28, 2021. The shares will vest on June 17, 2024, subject to the Reporting Person's continued service on the Issuer's board on such date.

F2 · balance_after: Includes restricted share units, which vest over various time periods.

SEC source: 0001104659-21-090248 · tm2121675-6_4seq1.xml · nonDerivative · entry 1

ZELEFSKY MICHAEL J · CIK 0001266801 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 104,197

F1 · shares: The Reporting Person was granted 13,774 restricted shares pursuant to the Issuer's 2016 Incentive Plan on June 28, 2021. The shares will vest on June 17, 2024, subject to the Reporting Person's continued service on the Issuer's board on such date.

F2 · balance_after: Includes restricted share units, which vest over various time periods.

SEC source: 0001104659-21-090239 · tm2121675-1_4seq1.xml · nonDerivative · entry 1

Chill Adam J. · CIK 0001626451 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 107,197

F1 · shares: The Reporting Person was granted 13,774 restricted shares pursuant to the Issuer's 2016 Incentive Plan on June 28, 2021. The shares will vest on June 17, 2024, subject to the Reporting Person's continued service on the Issuer's board on such date.

F2 · balance_after: Includes restricted share units, which vest over various time periods.

SEC source: 0001104659-21-090242 · tm2121675-3_4seq1.xml · nonDerivative · entry 1

Litchman Manuel MD · CIK 0001709485 · Director · President and CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 874,035

F1 · shares: Each restricted stock unit represents the right to receive one share of Common Stock of Mustang Bio, Inc. The restricted stock units will vest at different times over a period of 4 years.

F2 · balance_after: Includes restricted stock units, which vest over various time periods.

SEC source: 0001104659-21-051419 · tm2113178-1_4seq1.xml · nonDerivative · entry 6

Achenbach Brian · CIK 0001760132 · SVP, Fin. & Corp. Controller

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 131,053

F6 · kind: 2,423 shares were sold in connection with the vesting of 8,750 shares on March 27, 2021, these shares were sold by the Company's restricted stock administrator in order to satisfy Mr. Achenbach's tax withholding obligations. Mr. Achenbach had no discretion with respect to such sale, which was transacted automatically in accordance with the Company's corporate policies regarding the vesting of restricted stock.

F7 · price: Represents the weighted average sales price.

F8 · balance_after: Includes restricted share units, which vest over various time periods.

SEC source: 0001104659-21-035857 · tm219639d1_4seq1.xml · nonDerivative · entry 2

Litchman Manuel MD · CIK 0001709485 · Director · President and CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 825,408

F2 · price: Reflects the weighted average purchase price of multiple same-way open market purchase transactions effected by the Reporting Person on the same day at different prices through a purchase order executed by a broker-dealer. The Reporting Person reported on a single line all such transactions that occurred within a one-dollar price range. The range of prices for the purchase transactions on March 5, 2021, was $3.01 to $3.177. The Reporting Person hereby undertakes to provide upon request by the Securities Exchange Commission staff, the Issuer, or a shareholder of the Issuer, full information regarding the number of shares purchased at each separate price.

F3 · balance_after: Includes restricted share units, which vest over various time periods.

SEC source: 0001104659-21-035854 · tm219639d2_4seq1.xml · nonDerivative · entry 1

ROSENWALD LINDSAY A MD · CIK 0000941841 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 203,479

F1 · shares: These shares were acquired under the Mustang Bio, Inc. Employee Share Purchase Plan ("ESPP") for the ESPP purchase period beginning on September 1, 2020 and ending on February 28, 2021 in transactions that were exempt under both Rule 16b-3(d) and Rule 16b-3(c). In accordance with the terms of the ESPP, these shares were purchased at a price equal to 85% of the fair market value closing price of the Issuer's ordinary shares on September 1, 2020 (the purchase date of the offering period).

F2 · balance_after: Includes restricted share units, which vest over various time periods.

SEC source: 0001104659-21-035857 · tm219639d1_4seq1.xml · nonDerivative · entry 1

Litchman Manuel MD · CIK 0001709485 · Director · President and CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 659,846

F1 · shares: These shares were acquired under the Mustang Bio, Inc. Employee Share Purchase Plan ("ESPP") for the ESPP purchase period beginning on September 1, 2020 and ending on February 28, 2021 in transactions that were exempt under both Rule 16b-3(d) and Rule 16b-3(c). In accordance with the terms of the ESPP, these shares were purchased at a price equal to 85% of the fair market value closing price of the Issuer's ordinary shares on September 1, 2020 (the purchase date of the offering period).

F3 · balance_after: Includes restricted share units, which vest over various time periods.

SEC source: 0001104659-20-138581 · tm2039180-1_4.xml · nonDerivative · entry 3

Litchman Manuel MD · CIK 0001709485 · Director · President and CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 654,846

F4 · price: Reflects the weighted average purchase price of multiple same-way open market purchase transactions effected by the Reporting Person on the same day at different prices through a purchase order executed by a broker-dealer. The Reporting Person reported on a single line all such transactions that occurred within a one-dollar price range. The range of prices for the purchase transactions on December 15, 2020, was $2.85 to $2.98. The Reporting Person hereby undertakes to provide upon request by the Securities Exchange Commission staff, the Issuer, or a shareholder of the Issuer, full information regarding the number of shares purchased at each separate price.

F2 · balance_after: Includes restricted share units, which vest over various time periods.

SEC source: 0001104659-21-035850 · tm219639-3_4.xml · nonDerivative · entry 1

Achenbach Brian · CIK 0001760132 · SVP, Fin. & Corp. Controller

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 151,774

F1 · shares: Each restricted stock unit represents the right to receive one share of Common Stock of Mustang Bio, Inc..

F2 · balance_after: Includes restricted stock units, which vest over various time periods.

SEC source: 0001104659-20-135513 · tm2038479d1_4.xml · nonDerivative · entry 1

ROSENWALD LINDSAY A MD · CIK 0000941841 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 200,423

F1 · price: Reflects the weighted average purchase price of multiple same-way open market purchase transactions effected by the Reporting Person on the same day at different prices through a purchase order executed by a broker-dealer. The Reporting Person reported on a single line all such transactions that occurred within a one-dollar price range. The range of prices for the purchase transactions on December 14, 2020, was $2.59 to $2.73. The Reporting Person hereby undertakes to provide upon request by the Securities Exchange Commission staff, the Issuer, or a shareholder of the Issuer, full information regarding the number of shares purchased at each separate price.

F2 · balance_after: Includes restricted share units, which vest over various time periods.