aibioMustang Bio receives Nasdaq bid price deficiency notice
Tickers MBIO
Mustang Bio's common stock closed below $1.00 for 30 consecutive business days, and the company has until October 12, 2026 to regain compliance with the Nasdaq minimum bid price rule.
Key facts
- Company
- Mustang Bio, Inc. (NASDAQ: MBIO)
- News type
- Listings
- Primary source
- Mustang Bio, Inc. 8-K (2026-04-17)
Mustang Bio, Inc. (Nasdaq: MBIO) disclosed in a Current Report on Form 8-K, signed April 17, 2026, that it received a notice from the Listing Qualifications Department of The Nasdaq Stock Market LLC. The notice said the bid price of the company's common stock, par value $0.0001 per share, had closed below $1.00 per share for 30 consecutive business days. As a result, Mustang is not in compliance with Nasdaq Listing Rule 5550(a)(2), the minimum bid price requirement for continued listing on the Nasdaq Capital Market. The notice is dated April 15, 2026.
The grace period
The Nasdaq staff notice has no immediate effect on the listing of the common stock. Under Nasdaq Listing Rule 5810(c)(3)(A), Mustang has a 180-calendar day grace period, or until October 12, 2026, to regain compliance. Compliance requires a closing bid price of at least $1.00 per share for a minimum of ten consecutive business days, and generally not more than 20 consecutive business days, during the grace period.
If Mustang does not regain compliance by October 12, 2026, it may be eligible for an additional 180-calendar day period. To qualify, it must meet the initial listing criteria and the market value of publicly held shares requirement, and tell Nasdaq in writing that it will cure the deficiency, by a reverse stock split if necessary. If the company is not eligible, Nasdaq staff will send written notice that the common stock is subject to delisting. The company may then request a hearing before the Nasdaq Hearings Panel. A timely request would stay any further suspension or delisting action until the hearing process concludes and any extension the Panel grants expires.
What the company does
Mustang describes itself as a clinical-stage biopharmaceutical company focused on difficult-to-treat cancers, with a pipeline built on exclusive licenses from two research institutions. It includes MB-101, a CAR T therapy for solid tumors that targets IL13Rα2 and is developed in partnership with City of Hope National Medical Center. The company has also partnered with Nationwide Children's Hospital on MB-108, a herpes simplex virus type 1 oncolytic virus intended to boost the activity of MB-101 in patients with high-grade malignant brain tumors.
The combination, known as MB-109, received a safe-to-proceed letter from the FDA in October 2023 for a Phase 1 study in patients with IL13Rα2-positive recurrent glioblastoma and high-grade astrocytoma. The FDA granted orphan drug designation to MB-108 on November 7, 2024, and to MB-101 on July 7, 2025. Mustang's 10-K says that, because cell processing for MB-101 will revert to City of Hope, it is reasonable to assume the FDA will not require the lead-in cohort originally planned. The company is a majority-controlled subsidiary of Fortress Biotech, Inc.
Financial position
The XBRL data from the 10-K filed March 19, 2026 shows a net loss of negative $1.9 million for 2025, compared with negative $15.8 million for 2024. Cash from operations was negative $5.3 million for 2025 and negative $11.4 million for 2024. Year-end 2024 cash and cash equivalents were $6.8 million. The 10-K says the accumulated deficit was $398.6 million as of December 31, 2025, and that the company has not received approval to sell any product candidate or generated any product sales. The sources report no efficacy data for MB-109, whose trial the 10-K describes only as a possibility.
What comes next
Mustang said it intends to monitor the closing bid price of its common stock closely and to consider all available options to remedy the deficiency, but that no decision on any action has been made. The notice sets October 12, 2026 as the end of the initial grace period. The company warned in the filing that there can be no assurance it would be successful in maintaining the Nasdaq listing.
The 10-K also says Mustang is exploring an investigator-sponsored single-institution study of MB-109 with City of Hope and Nationwide that could start in the second quarter of 2026, a structure it ties to the termination of the lease on its Worcester, Massachusetts cell processing facility.