# EDGAR Filing Document

**Accession Number:** 0001429260
**File Stem:** 0001104659-26-000690
**Filing Date:** 2026-1
**Character Count:** 10999
**Document Hash:** 5a4258d3d7ffd4678b1241444da07db3
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001104659-26-000690.hdr.sgml**: 20260105

**ACCESSION NUMBER**: 0001104659-26-000690

**CONFORMED SUBMISSION TYPE**: SCHEDULE 13D/A

**PUBLIC DOCUMENT COUNT**: 1

**FILED AS OF DATE**: 20260105

**DATE AS OF CHANGE**: 20260105

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** MUSTANG BIO, INC.
- **CENTRAL INDEX KEY:** 0001680048
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 473828760
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D/A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-89875
- **FILM NUMBER:** 26507489

**BUSINESS ADDRESS:**
- **STREET 1:** 95 SAWYER RD
- **STREET 2:** SUITE 110
- **CITY:** WALTHAM
- **STATE:** MA
- **ZIP:** 02453
- **BUSINESS PHONE:** 7816524500

**MAIL ADDRESS:**
- **STREET 1:** 95 SAWYER RD
- **STREET 2:** SUITE 110
- **CITY:** WALTHAM
- **STATE:** MA
- **ZIP:** 02453
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Fortress Biotech, Inc.
- **CENTRAL INDEX KEY:** 0001429260
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 205157386
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D/A

**BUSINESS ADDRESS:**
- **STREET 1:** 1111 KANE CONCOURSE
- **STREET 2:** SUITE 301
- **CITY:** BAY HARBOR ISLANDS
- **STATE:** FL
- **ZIP:** 33154
- **BUSINESS PHONE:** 781-652-4500

**MAIL ADDRESS:**
- **STREET 1:** 1111 KANE CONCOURSE
- **STREET 2:** SUITE 301
- **CITY:** BAY HARBOR ISLANDS
- **STATE:** FL
- **ZIP:** 33154

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** CORONADO BIOSCIENCES INC
- **DATE OF NAME CHANGE:** 20080310

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## SCHEDULE 13D

### Under the Securities Exchange Act of 1934

**(Amendment No. 7)**

**Mustang Bio, Inc.**

*(Name of Issuer)*

**Common Stock, $0.0001 Par Value**

*(Title of Class of Securities)*

**62818Q302**

*(CUSIP Number)*

**Fortress Biotech, Inc.**<br>1111 Kane Concourse, Suite 301<br>Bay Harbor Islands FL 33154<br>(718) 652-4500

*(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)*

**01/02/2026**

*(Date of Event Which Requires Filing of this Statement)*

| **CUSIP No.** | **62818Q302** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Fortress Biotech, Inc.** | Name of reporting person<br>**Fortress Biotech, Inc.** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**OO** | Source of funds (See Instructions)<br>**OO** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**537243.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**535910.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**1333.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**537243.00** | Aggregate amount beneficially owned by each reporting person<br>**537243.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**8.0%** | Percent of class represented by amount in Row (11)<br>**8.0%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**CO** | Type of Reporting Person (See Instructions)<br>**CO** | |

---

**Comment for Reporting Person:** Sole Voting Power includes 1,333 shares of Issuer's common stock underlying Warrants and 250,000 shares of the Issuer's Class A preferred stock (both of which are described further below). The Issuer's Class A preferred stock is identical to its common stock other than as to voting rights, conversion rights and the PIK Dividend right. Each share of the Issuer's Class A preferred stock is entitled to vote the number of shares that is equal to one and one-tenth (1.1) times a fraction, the numerator of which is the sum of (A) the shares of the Issuer's outstanding common stock and (B) the whole shares of the Issuer's common stock into which any shares of outstanding Class A common shares and Class A preferred stock are convertible and the denominator of which is the number of shares of outstanding Class A preferred stock. Thus, the Class A preferred stock will at all times constitute a voting majority. The Reporting Person owns all outstanding shares of the Issuer's Class A preferred stock. As holders of Class A preferred stock, the Reporting Person will receive on each January 1 (each a "PIK Dividend Payment Date") until the date all outstanding Class A preferred stock is converted into common stock or redeemed (and the purchase price is paid in full), pro rata per share dividends paid in additional fully paid and nonassessable shares of Issuer common stock ("PIK Dividends") such that the aggregate number of shares of common stock issued pursuant to such PIK Dividend is equal to two and one-half percent (2.5%) of the Issuer's fully-diluted outstanding capitalization on the date that is one (1) business day prior to any PIK Dividend Payment Date. An aggregate 1,333 shares of Issuer common stock underlie the Common Stock Warrants dated July 15, 2015, as amended by the Amended and Restated Common Stock Warrant dated December 12, 2016, issued by the Reporting Person to Lindsay A. Rosenwald, M.D., the Reporting Person's Chairman, President and Chief Executive Officer and Michael S. Weiss, the Reporting Person's Executive Vice Chairman, Strategic Development, pursuant to the Fortress Biotech, Inc. Long-Term Incentive Plan (the "Warrants"). The Warrants, which have an exercise price of $110.25 per share, are exercisable until July 15, 2035. The Reporting Person must reserve from its holdings of the Issuer's common stock the shares underlying the Warrants until the Warrants are exercised. The foregoing description of the Warrants is not complete and is qualified in its entirety by reference to the full text of the form of the Amended and Restated Common Stock Warrant incorporated herein by reference as Exhibit 7.03. Mr. Weiss has served Chairman of the Issuer's Board of Directors since May 2015 and as the Executive Chairman since January 2017. Dr. Rosenwald has served as a member of the Issuer's Board of Directors since the Issuer's conception.

Sole Dispositive Power excludes the 1,333 shares of Issuer's common stock underlying the warrants.

Shared Dispositive Power consists solely of the 1,333 shares of Issuer's common stock underlying the Warrants.

All percentage calculations set forth herein are based upon 6,453,701 shares of the Issuer's common stock as of November 5, 2025 as reported by the Issuer on its Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on November 7, 2025, 845,385 shares of the Issuer's Class A common stock, convertible into 1,127 shares of the Issuer's common stock, the conversion of all 250,000 shares of Issuer's Class A preferred stock into 333 shares of the Issuer's common stock, and 278,385 shares of Issuer's common stock issued as an Annual Equity Grant (defined below).

This Amendment No. 7 to Schedule 13D (this "Amendment No. 6") amends and supplements the Schedule 13D filed on May 26, 2017 (as amended and supplemented through the date of this Amendment No. 7, collectively, the "Schedule 13D") relating to the Common Stock of Mustang Bio, Inc. (the "Issuer"), by Fortress Biotech, Inc. (the "Reporting Person"). Except as specifically provided herein, this Amendment No. 7 does not modify any of the information previously reported on the Schedule 13D. Capitalized terms used but not defined herein shall have the same meanings as are ascribed to them in the Schedule 13D, as applicable

**Item 1. Security and Issuer**

**(a) Title of Class of Securities:**
Common Stock, $0.0001 Par Value

**(b) Name of Issuer:**
Mustang Bio, Inc.

**(c) Address of Issuer's Principal Executive Offices:**
95 Sawyer Road, Waltham, MA, 02453

**Item 4. Purpose of Transaction**

The Reporting Person is party to that certain Second Amended and Restated Founders Agreement with the Issuer (as amended, the "Founders Agreement"), in connection with the Issuer's formation.  Pursuant to the Issuer's Amended and Restated Certificate of Incorporation (as amended, the "Charter"), the Issuer issues annually to the Reporting Person shares of common stock equal to two and one-half percent (2.5%) of the fully-diluted outstanding equity of the Issuer, as measured as of the date of such issuance (the "Annual Equity Grant").

The foregoing description of the Charter and Founders Agreement are qualified in its entirety by reference to the full text of the Charter and Founders Agreement which are incorporated herein by reference as Exhibits 7.01, 7.02, and 7.04.

**Item 5. Interest in Securities of the Issuer**

**(a)**
The Reporting Person is the beneficial owner of 536,910 shares of the Issuer's common stock (including 250,000 shares of Class A preferred stock, which are convertible into 333 shares of the Issuer's common stock), representing beneficial ownership of 8.0%% of all outstanding shares of the Issuer's common stock.

**(b)**
The Reporting Person has sole voting power of 536,910 shares of the Issuer's common stock (including 250,000 shares of Class A preferred stock, which are convertible into 333 shares of the Issuer's common stock).

**(c)**
Not applicable.

**Item 6. Contracts, Arrangements, Understandings or Relationships With Respect to Securities of the Issuer.**

Reference is made to the Founders Agreement in Item 3 and the Warrants in the Comments above.

### SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Fortress Biotech, Inc.

**Signature:** /s/ Lindsay A. Rosenwald

**Name/Title:** Lindsay A. Rosenwald, M.D. / Chairman, President and Chief Executive Officer

**Date:** 01/05/2026