Gossamer Bio enacts 1-for-80 reverse split for Nasdaq
Gossamer Bio has effected a 1-for-80 reverse split and major authorized share reduction to support efforts to regain Nasdaq minimum bid price compliance.
Rhea-AI Filing Summary
Gossamer Bio, Inc. (GOSS) has implemented a 1-for-80 reverse stock split of its common stock, effective at 11:59 p.m. Eastern Time on September 10, 2026, along with a proportionate reduction in authorized share counts. Every 80 pre-split shares have been reclassified into 1 post-split share, with fractional positions rounded up to the nearest whole share.
The number of authorized common shares was reduced from 4,000,000,000 to 50,000,000, and total authorized capital stock from 4,070,000,000 to 120,000,000. Conversion rates and exercise prices on convertible notes, warrants, prefunded warrants, and equity awards were proportionately adjusted, and plan reserves were reduced. The stock is expected to trade on a split-adjusted basis on Nasdaq under “GOSS” on September 11, 2026, and the reverse split is intended to help regain compliance with Nasdaq’s $1.00 minimum bid price requirement by the October 5, 2026 compliance date.
Positive
- None.
Negative
- Nasdaq listing at risk due to bid price: The reverse split is expressly intended to help regain compliance with Nasdaq’s $1.00 minimum bid price requirement by October 5, 2026, and the company notes there is no assurance it will satisfy this standard or maintain its Nasdaq Global Select Market listing.
Filing Explained
The completed 1-for-80 reverse stock split leaves each holder’s percentage ownership and proportional voting power unchanged, apart from minor fractional-share effects, so the filing does not disclose dilution from the split.
8-K Event Classification
4 items: 3.03, 5.03, 8.01, 9.01
4 items
Item 3.03
Material Modification to Rights of Security Holders
Securities
A change was made that materially affects the rights of existing shareholders (e.g., dividend rights, voting rights).
Item 5.03
Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year
Governance
The company amended its charter documents, bylaws, or changed its fiscal year.
Item 8.01
Other Events
Other
Voluntary disclosure of events the company deems important to shareholders but not covered by other items.
Item 9.01
Financial Statements and Exhibits
Exhibits
Financial statements, pro forma financial information, or exhibit attachments filed with this report.
Key Figures
Reverse stock split ratio: 1-for-80 (every 80 old shares into 1 new share)
Authorized common shares after reduction: 50,000,000 shares
Total authorized capital stock after reduction: 120,000,000 shares
+3 more
6 metrics
Reverse stock split ratio
1-for-80 (every 80 old shares into 1 new share)
Reverse stock split of Gossamer Bio common stock effective September 10, 2026
Authorized common shares after reduction
50,000,000 shares
Reduced from 4,000,000,000 authorized common shares in Authorized Share Reduction
Total authorized capital stock after reduction
120,000,000 shares
Reduced from 4,070,000,000 total authorized shares of capital stock
Nasdaq minimum bid price requirement
$1.00 per share
Closing bid price must be at least $1.00 for 10 consecutive business days
Nasdaq compliance deadline
October 5, 2026
Date by which the minimum bid price requirement must be met for continued listing
Effective time of reverse split
11:59 p.m. Eastern Time on September 10, 2026
Time when the Charter Amendment and reverse split became effective
Key Terms
reverse stock split, Authorized Share Reduction, minimum bid price requirement, convertible notes, +1 more
5 terms
reverse stock split financial
"to effect the 1-for-80 reverse stock split of the Company’s common stock"
A reverse stock split reduces a company's number of outstanding shares while raising the price per share proportionally, so the total value of each investor's holding is unchanged; a 1-for-10 split turns 100 shares worth $1 each into 10 shares worth $10 each. Companies often do this to regain compliance with an exchange's minimum price rule or to attract investors who avoid very low-priced stocks.
minimum bid price requirement regulatory
"to help the Company regain compliance with the minimum bid price requirement for continued listing"
A minimum bid price requirement is a rule that a stock must trade above a set price for a specified period to stay listed on an exchange. It matters to investors because falling below that threshold can trigger warnings or removal from the exchange, which can cut liquidity, reduce visibility, and often lead to sharper declines in share value—think of it like a venue’s minimum dress code that, if not met, can bar a performer from the stage.
convertible notes financial
"the Company’s outstanding convertible notes (including the 5.00% Convertible Senior Notes due 2027"
Convertible notes are a type of short-term loan that a company receives from investors, which can later be turned into company shares instead of being paid back in cash. They matter to investors because they offer a way to support a company early on while giving the potential to own a stake in its success if the company grows and later raises more funding.
CUSIP number financial
"under the existing trading symbol “GOSS” and a new CUSIP number of 38341P 201"
A CUSIP number is a nine-character code that uniquely identifies a specific U.S. or Canadian stock, bond, or other security, similar to a barcode or a social-security number for a financial instrument. It matters to investors because it removes confusion between similar securities, ensures trades and settlements are applied to the correct issue, and helps locate official documents and transaction records quickly.
FAQ
What reverse stock split did Gossamer Bio (GOSS) implement?
Gossamer Bio implemented a 1-for-80 reverse stock split of its common stock, effective at 11:59 p.m. Eastern Time on September 10, 2026, reclassifying every 80 existing shares into 1 new share and rounding fractional positions up to the nearest whole share.
When will GOSS begin trading on a split-adjusted basis?
Shares of Gossamer Bio common stock are expected to begin trading on a split-adjusted basis on the Nasdaq Global Select Market at market open on September 11, 2026, under the existing ticker symbol “GOSS” and a new CUSIP number 38341P 201.
Why did Gossamer Bio carry out the reverse stock split?
The reverse stock split is intended to help Gossamer Bio regain compliance with Nasdaq’s minimum bid price requirement for continued listing, which requires a closing bid price of at least $1.00 per share for a minimum of 10 consecutive business days before October 5, 2026.
Does the GOSS reverse split change stockholders’ ownership percentage?
The company states the reverse stock split had no effect on the par value of the common stock and that each stockholder’s percentage ownership interest and proportional voting power remains unchanged, except for minor changes resulting from the treatment of fractional shares.
How were GOSS convertible notes, warrants, and equity awards adjusted?
Upon effectiveness of the reverse split, the conversion rates of outstanding convertible notes, the number of shares issuable and exercise prices under warrants, prefunded warrants, and equity awards, and the shares reserved under equity plans were all proportionately adjusted to reflect the 1-for-80 ratio.
AI-generated analysis. How Rhea-AI works. Not financial advice.
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549
FORM 8-K
CURRENT REPORT
Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934
Date of Report (Date of earliest event reported): September 10, 2026
(Exact name of Registrant as Specified in Its Charter)
| (State or Other Jurisdiction of Incorporation) | (Commission File Number) | (IRS Employer Identification No.) | ||||||
(Address of Principal Executive Offices) (Zip Code)
(858 ) 684-1300
(Registrant’s Telephone Number, Including Area Code)
N/A
(Former Name or Former Address, if Changed Since Last Report)
Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:
| Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) | |||||
| Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) | |||||
| Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) | |||||
| Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) | |||||
Securities registered pursuant to Section 12(b) of the Act:
| Title of each class | Trading Symbol(s) | Name of each exchange on which registered | ||||||||||||
Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).
Emerging growth company ☐
If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐
Item 3.03 Material Modification to Rights of Security Holders.
To the extent required by Item 3.03 of Form 8-K, the information set forth under Item 5.03 of this Current Report on Form 8-K is incorporated by reference into this Item 3.03.
Item 5.03 Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year.
As previously disclosed, on September 9, 2026, Gossamer Bio, Inc. (the “Company”) announced that its board of directors (the “Board”) had selected a 1-for-80 ratio for the previously approved reverse stock split of the Company’s common stock, par value $0.0001 per share (the “Common Stock”). On September 10, 2026, the Company filed with the Secretary of State of the State of Delaware a Certificate of Amendment to its Amended and Restated Certificate of Incorporation (the “Charter Amendment”) to effect the 1-for-80 reverse stock split of the Common Stock (the “Reverse Stock Split”) and a proportionate reduction in the number of authorized shares of Common Stock (and a corresponding decrease in the total number of authorized shares of capital stock) (the “Authorized Share Reduction”). The Charter Amendment became effective at 11:59 p.m. Eastern Time on September 10, 2026 (the “Effective Time”). The foregoing description of the Charter Amendment is not complete and is subject to, and qualified in its entirety by, the complete text of the Charter Amendment, which is filed as Exhibit 3.1 to this Current Report on Form 8-K and incorporated herein by reference.
In connection with the Reverse Stock Split, every 80 shares of Common Stock issued and outstanding immediately prior to the Effective Time were automatically reclassified and combined into 1 share of Common Stock. No fractional shares of Common Stock will be issued as a result of the Reverse Stock Split. Instead, the Company will issue to holders of record who were entitled to a fraction of a share as a result of the Reverse Stock Split, a fraction of a share of Common Stock as is necessary to round up to the nearest whole share. For shares held through The Depository Trust Company ("DTC"), fractions of shares will be issued as is necessary to round up to the nearest whole share at the DTC participant level. Brokers, banks or other nominees holding shares in "street name" will be instructed to effect the Reverse Stock Split for their beneficial holders; however, such brokers, banks or other nominees may apply their own specific procedures for processing the Reverse Stock Split.
The Common Stock is expected to begin trading on a split-adjusted basis on the Nasdaq Global Select Market at market open on September 11, 2026 under the existing trading symbol “GOSS” and a new CUSIP number of 38341P 201.
Upon the effectiveness of the Reverse Stock Split, the conversion rates of the Company’s outstanding convertible notes (including the 5.00% Convertible Senior Notes due 2027 and the 7.50% Convertible Senior Secured First Lien Notes due 2030), the number of shares of Common Stock issuable upon exercise of outstanding warrants and prefunded warrants and the exercise prices thereof, and the number of shares subject to outstanding equity awards under the Company’s equity incentive plans (and the applicable exercise prices thereof), were each proportionately adjusted pursuant to their respective terms and as determined by the Board to reflect the 1-for-80 reverse stock split ratio. In addition, the number of shares reserved for future issuance under the Company’s equity incentive plans was proportionately reduced.
In connection with the Authorized Share Reduction, the number of authorized shares of Common Stock was reduced from 4,000,000,000 to 50,000,000, and the total number of authorized shares of capital stock was correspondingly reduced from 4,070,000,000 to 120,000,000.
The Reverse Stock Split is intended to help the Company regain compliance with the minimum bid price requirement for continued listing on the Nasdaq Global Select Market. To regain compliance, the closing bid price of the Common Stock must be at least $1.00 per share for a minimum of 10 consecutive business days before the compliance date, which is October 5, 2026. There can be no assurance that the Company will regain compliance with the minimum bid price requirement, that the Common Stock will continue to meet the Nasdaq minimum bid price requirement, or that the Common Stock will remain listed on the Nasdaq Global Select Market.
Item 8.01 Other Events.
On September 11, 2026, the Company issued a press release announcing the effectiveness of the Reverse Stock Split and Authorized Share Reduction. A copy of the press release is attached hereto as Exhibit 99.1 and is incorporated herein by reference.
* * *
Note Regarding Forward-Looking Statements.
The Company cautions you that statements contained in this report regarding matters that are not historical facts are forward-looking statements. These statements are based on the Company’s current beliefs and expectations. Such forward-looking statements include, but are not limited to, statements regarding: the expected commencement of trading of the Common Stock on a split-adjusted basis, the anticipated impact of the Reverse Stock Split on the Company’s ability to regain compliance with the Nasdaq minimum bid price requirement, and the continued listing of the Common Stock on the Nasdaq Global Select Market. The inclusion of forward-looking statements should not be regarded as a representation by Gossamer that any of its plans will be achieved. Actual results may differ from those set forth in this report due to the risks and uncertainties inherent in Gossamer’s business, including, without limitation: the Reverse Stock Split may not result in a sustained increase in the price of the Company’s Common Stock and may not satisfy the Nasdaq minimum bid price requirement; the reverse stock split may impact our results of operations, business operations and reputation as well as the trading prices and volatility of the common stock; unstable market and economic conditions and changes in healthcare legislation, tariffs and trade policies may adversely affect the Company’s business and financial condition and the broader economy and biotechnology industry; and other risks described in the Company’s filings with the Securities and Exchange Commission (“SEC”), including under the heading “Risk Factors” in the Company’s annual report on Form 10-K and any subsequent filings with the SEC. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof, and Gossamer undertakes no obligation to update such statements to reflect events that occur or circumstances that exist after the date hereof. All forward-looking statements are qualified in their entirety by this cautionary statement, which is made under the safe harbor provisions of the Private Securities Litigation Reform Act of 1995.
Item 9.01 Financial Statements and Exhibits.
(d) Exhibits.
Exhibit Number | Description | |||||||
| 3.1 | Certificate of Amendment to the Amended and Restated Certificate of Incorporation of Gossamer Bio, Inc., effective September 10, 2026 | |||||||
| 99.1 | Press release issued by Gossamer Bio, Inc., dated September 11, 2026 | |||||||
| 104 | Cover page interactive data file (embedded with the inline XBRL document) | |||||||
SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.
| GOSSAMER BIO, INC. | |||||||||||
| Date: September 11, 2026 | By: | /s/ Bryan Giraudo | |||||||||
| Bryan Giraudo | |||||||||||
| Chief Financial Officer and Chief Operating Officer | |||||||||||
Exhibit 99.1
Gossamer Bio Announces Effectiveness of 1-for-80 Reverse Stock Split
September 11, 2026
SAN DIEGO—(BUSINESS WIRE)— September 11, 2026 — Gossamer Bio, Inc. (Nasdaq: GOSS) (the “Company” or “Gossamer”), a clinical-stage biopharmaceutical company focused on the development and commercialization of seralutinib for the treatment of pulmonary arterial hypertension and pulmonary hypertension associated with interstitial lung disease, today announced that it has filed a Certificate of Amendment to its Amended and Restated Certificate of Incorporation with the Secretary of State of the State of Delaware to effect the previously announced 1-for-80 reverse stock split of the Company’s common stock, par value $0.0001 per share, and a proportionate reduction in the number of authorized shares of the Company’s common stock (and a corresponding decrease in the total number of authorized shares of capital stock). The reverse stock split and the reduction in authorized shares became effective at 11:59 p.m. Eastern Time on September 10, 2026. Shares of the Company’s common stock are expected to begin trading on a split-adjusted basis on the Nasdaq Global Select Market at market open on September 11, 2026 under the existing trading symbol “GOSS” and a new CUSIP number of 38341P 201.
In connection with the reverse stock split, every 80 shares of the Company’s common stock issued and outstanding immediately prior to the effective time were automatically reclassified and combined into 1 share of common stock. No fractional shares of common stock will be issued as a result of the reverse stock split. Instead, the Company will issue to holders of record who were entitled to a fraction of a share as a result of the reverse stock split, a fraction of a share of common stock as is necessary to round up to the nearest whole share. For shares held through The Depository Trust Company ("DTC"), fractions of shares will be issued as is necessary to round up to the nearest whole share at the DTC participant level. Brokers, banks or other nominees holding shares in "street name" will be instructed to effect the reverse stock split for their beneficial holders; however, such brokers, banks or other nominees may apply their own specific procedures for processing the reverse stock split.
Upon the effectiveness of the reverse stock split, the conversion rates of the Company’s outstanding convertible notes (including the 5.00% Convertible Senior Notes due 2027 and the 7.50% Convertible Senior Secured First Lien Notes due 2030), the number of shares of common stock issuable upon exercise of outstanding warrants and prefunded warrants and the exercise prices thereof, and the number of shares subject to outstanding equity awards under the Company’s equity incentive plans (and the
applicable exercise prices thereof), were each proportionately adjusted pursuant to their respective terms and as determined by the Company’s board of directors to reflect the 1-for-80 reverse stock split ratio. In addition, the number of shares reserved for future issuance under the Company’s equity incentive plans was proportionately reduced.
The reverse stock split had no effect on the par value of the Company’s common stock, and each stockholder’s percentage ownership interest in the Company and proportional voting power remains unchanged, except for minor changes resulting from the treatment of fractional shares.
In connection with the reverse stock split, the number of authorized shares of the Company’s common stock was reduced from 4,000,000,000 to 50,000,000, and the total number of authorized shares of capital stock was correspondingly reduced from 4,070,000,000 to 120,000,000.
The reverse stock split is intended to help the Company regain compliance with the minimum bid price requirement for continued listing on the Nasdaq Global Select Market. To regain compliance, the closing bid price of the Company’s common stock must be at least $1.00 per share for a minimum of 10 consecutive business days before the compliance date, which is October 5, 2026. There can be no assurance that the Company will regain compliance with the minimum bid price requirement, that its common stock will continue to meet the Nasdaq minimum bid price requirement, or that its common stock will remain listed on the Nasdaq Global Select Market.
Computershare Trust Company, N.A. is acting as the transfer agent and, along with its affiliate Computershare, Inc., the exchange agent for the reverse stock split. Stockholders who hold registered shares in book-entry form at Computershare Trust Company, N.A. are not required to take any action to receive split-adjusted shares. Stockholders who hold shares through a broker, bank or other nominee will have their positions automatically adjusted and are not required to take any action.
About Gossamer Bio
Gossamer Bio is a clinical-stage biopharmaceutical company focused on the development and commercialization of seralutinib for the treatment of pulmonary arterial hypertension and pulmonary hypertension associated with interstitial lung disease. Its goal is to be an industry leader in, and to enhance the lives of patients living with, pulmonary hypertension.
Forward-Looking Statements
Gossamer cautions you that statements contained in this press release regarding matters that are not historical facts are forward-looking statements. These statements are based on the Company’s current beliefs and expectations. Such forward-looking statements include, but are not limited to, statements regarding: the expected commencement of trading of the Company’s common stock on a split-adjusted basis, the anticipated impact of the reverse stock split on the Company’s ability to regain compliance with the Nasdaq minimum bid price requirement, and the continued listing of the Company’ common stock on the Nasdaq Global Select Market. The inclusion of forward-looking statements should not be regarded as a representation by Gossamer that any of its plans will be achieved. Actual results may differ from those set forth in this press release due to the risks and uncertainties inherent in Gossamer’s business, including, without limitation: the reverse stock split may not result in a sustained increase in the price of the Company’s common stock and may not satisfy the Nasdaq minimum bid price requirement; the reverse stock split may impact our results of operations, business operations and reputation as well as the trading prices and volatility of the common stock; unstable market and economic conditions and changes in healthcare legislation, tariffs and trade policies may adversely affect the Company’s business and financial condition and the broader economy and biotechnology industry; and other risks described in the Company’s prior press releases and the Company’s filings with the Securities and Exchange Commission (“SEC”), including under the heading “Risk Factors” in the Company’s annual report on Form 10-K and any subsequent filings with the SEC. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof, and Gossamer undertakes no obligation to update such statements to reflect events that occur or circumstances that exist after the date hereof. All forward-looking statements are qualified in their entirety by this cautionary statement, which is made under the safe harbor provisions of the Private Securities Litigation Reform Act of 1995.
For Investors and Media:
Bryan Giraudo, Chief Financial Officer & Chief Operating Officer
Gossamer Bio Investor Relations
ir@gossamerbio.com