Gossamer Bio sells $25M in private offering

Gossamer Bio is conducting a sizable private exempt offering under Regulation D Rule 506(b), with $25 million sold and $125 million remaining.

Rhea-AI Filing Summary

Gossamer Bio, Inc. (GOSS), a Delaware biotechnology corporation, filed a new notice of an exempt securities offering under Regulation D, Rule 506(b).

The offering involves options, warrants or other rights to acquire securities and the securities issuable upon exercise. The company reports that $25,000,000 of securities have been sold and that $125,000,000 remain available to be sold. The date of first sale is listed as August 20, 2026. Leerink Partners LLC and Cantor Fitzgerald & Co. are identified in the sales compensation section, and stated finders’ fees are $0.

Key Figures

Total Amount Sold: $25,000,000 Total Remaining to be Sold: $125,000,000 Exemption Relied Upon: Rule 506(b) of Regulation D +2 more

5 metrics

Total Amount Sold $25,000,000 Securities sold in this exempt offering

Total Remaining to be Sold $125,000,000 Additional securities that may be sold in the offering

Exemption Relied Upon Rule 506(b) of Regulation D Federal exemption claimed for the offering

Date of First Sale August 20, 2026 First sale date for this exempt offering

Finders’ Fees $0 Stated finders’ fees expenses for the offering

Key Terms

Rule 506(b), Regulation D, covered securities, Investment Company Act of 1940, +1 more

5 terms

Rule 506(b) regulatory

"X | Rule 506(b) | Rule 506(c) | Securities Act Section 4(a)(5)"

Rule 506(b) is a U.S. securities exemption that lets companies sell shares or debt privately without full public registration, provided sales are primarily to accredited investors, up to 35 non‑accredited but financially knowledgeable buyers, and there is no public advertising or solicitation. It matters to investors because offerings under 506(b) usually include less public disclosure than registered securities—like buying from a private seller rather than a retail store—so buyers must do more of their own fact‑checking and rely on their financial sophistication.

Regulation D regulatory

"if the issuer is claiming a Regulation D exemption for the offering"

Regulation D is a set of rules that govern how companies can raise money from investors without going through the full process required for public stock offerings. It provides simplified options for private placements, making it easier for companies to seek investments from a smaller group of investors. For investors, it offers opportunities to invest in private companies, often with fewer restrictions, but also with different levels of risk and disclosure.

covered securities regulatory

"If the securities that are the subject of this Form D are "covered securities""

Investment Company Act of 1940 regulatory

"Is the issuer registered as an investment company under the Investment Company Act of 1940?"

A U.S. federal law that sets the rulebook for pooled investment vehicles such as mutual funds, exchange-traded funds and similar money managers, requiring them to register with regulators, disclose holdings and fees, limit conflicts of interest, and follow governance standards. It matters to investors because these protections and transparency rules act like a referee and scoreboard, helping people compare funds, trust that managers follow fair practices, and spot hidden costs or risks.

Business Trust financial

"General Partnership | Business Trust | Other (Specify)"

FAQ

What type of securities is Gossamer Bio (GOSS) offering in this Form D?

Gossamer Bio is offering options, warrants or other rights to acquire another security and the securities to be acquired upon exercise, as part of an exempt private offering under Regulation D, Rule 506(b).

How much has Gossamer Bio (GOSS) sold so far in this exempt offering?

Gossamer Bio reports a Total Amount Sold of $25,000,000 in this exempt private offering, as disclosed in the offering and sales amounts section of the notice.

What is the remaining amount available to be sold in Gossamer Bio’s (GOSS) offering?

The company reports a Total Remaining to be Sold of $125,000,000 in this exempt offering, indicating additional securities may be sold up to that amount.

Under which exemption is Gossamer Bio (GOSS) conducting this private offering?

Gossamer Bio is relying on Rule 506(b) of Regulation D under the Securities Act of 1933, as indicated in the federal exemptions and exclusions section.

When did Gossamer Bio’s (GOSS) exempt offering first close a sale?

The notice lists the Date of First Sale as August 20, 2026 for this Regulation D Rule 506(b) exempt securities offering.

Which firms are involved in sales compensation for Gossamer Bio’s (GOSS) Form D offering?

The sales compensation section names Leerink Partners LLC and Cantor Fitzgerald & Co.. The filing also reports Finders’ Fees of $0.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 09/04/2026 - 04:52 PM Accepted by SEC EDGAR 09/04/2026 - 04:50 PM Learn about SEC filing dates

The Securities and Exchange Commission has not necessarily reviewed the information in this filing and has not determined if it is accurate and complete.
The reader should not assume that the information is accurate and complete.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
Intentional misstatements or omissions of fact constitute federal criminal violations. See 18 U.S.C. 1001.

FORM D

Notice of Exempt Offering of Securities

OMB APPROVAL

OMB Number:			3235-0076
Estimated average burden
hours per response:			4.00

1. Issuer's Identity

CIK (Filer ID Number)

Previous Names

X None

Entity Type

0001728117

X	Corporation
	Limited Partnership
	Limited Liability Company
	General Partnership
	Business Trust
	Other (Specify)

Name of Issuer

Gossamer Bio, Inc.

Jurisdiction of Incorporation/Organization

DELAWARE

Year of Incorporation/Organization

X	Over Five Years Ago
	Within Last Five Years (Specify Year)
	Yet to Be Formed

2. Principal Place of Business and Contact Information

Name of Issuer
Gossamer Bio, Inc.
Street Address 1		Street Address 2
3115 Merryfield Row, Suite 120
City	State/Province/Country	ZIP/PostalCode	Phone Number of Issuer
San Diego	CALIFORNIA	92121	(858) 684-1300

3. Related Persons

Last Name	First Name	Middle Name
Hasnain	Faheem
Street Address 1	Street Address 2
3115 Merryfield Row, Suite 120
City	State/Province/Country	ZIP/PostalCode
San Diego	CALIFORNIA	92121

Relationship: X Executive Officer X Director Promoter

Clarification of Response (if Necessary):

Last Name	First Name	Middle Name
Cox	Russell
Street Address 1	Street Address 2
3115 Merryfield Row, Suite 120
City	State/Province/Country	ZIP/PostalCode
San Diego	CALIFORNIA	92121

Relationship: Executive Officer X Director Promoter

Clarification of Response (if Necessary):

Last Name	First Name	Middle Name
Daniel	Thomas
Street Address 1	Street Address 2
3115 Merryfield Row, Suite 120
City	State/Province/Country	ZIP/PostalCode
San Diego	CALIFORNIA	92121

Relationship: Executive Officer X Director Promoter

Clarification of Response (if Necessary):

Last Name	First Name	Middle Name
Drynan	Skye	J.
Street Address 1	Street Address 2
3115 Merryfield Row, Suite 120
City	State/Province/Country	ZIP/PostalCode
San Diego	CALIFORNIA	92121

Relationship: Executive Officer X Director Promoter

Clarification of Response (if Necessary):

Last Name	First Name	Middle Name
Milligan	Sandra
Street Address 1	Street Address 2
3115 Merryfield Row, Suite 120
City	State/Province/Country	ZIP/PostalCode
San Diego	CALIFORNIA	92121

Relationship: Executive Officer X Director Promoter

Clarification of Response (if Necessary):

Last Name	First Name	Middle Name
Nathan	Steven	D.
Street Address 1	Street Address 2
3115 Merryfield Row, Suite 120
City	State/Province/Country	ZIP/PostalCode
San Diego	CALIFORNIA	92121

Relationship: Executive Officer X Director Promoter

Clarification of Response (if Necessary):

Last Name	First Name	Middle Name
Quisel	John
Street Address 1	Street Address 2
3115 Merryfield Row, Suite 120
City	State/Province/Country	ZIP/PostalCode
San Diego	CALIFORNIA	92121

Relationship: Executive Officer X Director Promoter

Clarification of Response (if Necessary):

Last Name	First Name	Middle Name
Giraudo	Bryan
Street Address 1	Street Address 2
3115 Merryfield Row, Suite 120
City	State/Province/Country	ZIP/PostalCode
San Diego	CALIFORNIA	92121

Relationship: X Executive Officer Director Promoter

Clarification of Response (if Necessary):

Last Name	First Name	Middle Name
Waage	Christian
Street Address 1	Street Address 2
3115 Merryfield Row, Suite 120
City	State/Province/Country	ZIP/PostalCode
San Diego	CALIFORNIA	92121

Relationship: X Executive Officer Director Promoter

Clarification of Response (if Necessary):

Last Name	First Name	Middle Name
Smith	Robert
Street Address 1	Street Address 2
3115 Merryfield Row, Suite 120
City	State/Province/Country	ZIP/PostalCode
San Diego	CALIFORNIA	92121

Relationship: X Executive Officer Director Promoter

Clarification of Response (if Necessary):

Last Name	First Name	Middle Name
Peterson	Caryn
Street Address 1	Street Address 2
3115 Merryfield Row, Suite 120
City	State/Province/Country	ZIP/PostalCode
San Diego	CALIFORNIA	92121

Relationship: X Executive Officer Director Promoter

Clarification of Response (if Necessary):

4. Industry Group

Agriculture

Banking & Financial Services

Commercial Banking

Insurance

Investing

Investment Banking

Pooled Investment Fund

Is the issuer registered as
an investment company under
the Investment Company
Act of 1940?

Yes No

Other Banking & Financial Services

Business Services

Energy

Coal Mining

Electric Utilities

Energy Conservation

Environmental Services

Oil & Gas

Other Energy

	Health Care
	X Biotechnology
	Health Insurance
	Hospitals & Physicians
	Pharmaceuticals
	Other Health Care
	Manufacturing
	Real Estate
	Commercial
	Construction
	REITS & Finance
	Residential
	Other Real Estate

Retailing

Restaurants

Technology

Computers

Telecommunications

Other Technology

Travel

Airlines & Airports

Lodging & Conventions

Tourism & Travel Services

Other Travel

Other

5. Issuer Size

Revenue Range		OR	Aggregate Net Asset Value Range
	No Revenues			No Aggregate Net Asset Value
	$1 - $1,000,000			$1 - $5,000,000
	$1,000,001 - $5,000,000			$5,000,001 - $25,000,000
	$5,000,001 - $25,000,000			$25,000,001 - $50,000,000
	$25,000,001 - $100,000,000			$50,000,001 - $100,000,000
	Over $100,000,000			Over $100,000,000
X	Decline to Disclose			Decline to Disclose
	Not Applicable			Not Applicable

6. Federal Exemption(s) and Exclusion(s) Claimed (select all that apply)

		Rule 504(b)(1) (not (i), (ii) or (iii))
		Rule 504 (b)(1)(i)
		Rule 504 (b)(1)(ii)
		Rule 504 (b)(1)(iii)
	X	Rule 506(b)
		Rule 506(c)
		Securities Act Section 4(a)(5)

Investment Company Act Section 3(c)

Section 3(c)(1) Section 3(c)(9)

Section 3(c)(2) Section 3(c)(10)

Section 3(c)(3) Section 3(c)(11)

Section 3(c)(4) Section 3(c)(12)

Section 3(c)(5) Section 3(c)(13)

Section 3(c)(6) Section 3(c)(14)

Section 3(c)(7)

7. Type of Filing

X	New Notice			Date of First Sale	2026-08-20				First Sale Yet to Occur
	Amendment

8. Duration of Offering

Does the Issuer intend this offering to last more than one year? Yes X No

9. Type(s) of Securities Offered (select all that apply)

	Equity		Pooled Investment Fund Interests
	Debt		Tenant-in-Common Securities
X	Option, Warrant or Other Right to Acquire Another Security		Mineral Property Securities
X	Security to be Acquired Upon Exercise of Option, Warrant or Other Right to Acquire Security		Other (describe)

10. Business Combination Transaction

Is this offering being made in connection with a business combination transaction, such as a merger, acquisition or exchange offer? Yes X No

Clarification of Response (if Necessary):

11. Minimum Investment

Minimum investment accepted from any outside investor $0 USD

12. Sales Compensation

Recipient	Recipient CRD Number None
Leerink Partners LLC	39011
(Associated) Broker or Dealer X None	(Associated) Broker or Dealer CRD Number X None
None	None
Street Address 1	Street Address 2
53 State St., 40th Floor
City	State/Province/Country	ZIP/Postal Code
Boston	MASSACHUSETTS	02109
State(s) of Solicitation (select all that apply) Check "All States" or check individual States X All States	X Foreign/non-US

Recipient	Recipient CRD Number None
Cantor Fitzgerald & Co.	134
(Associated) Broker or Dealer X None	(Associated) Broker or Dealer CRD Number X None
None	None
Street Address 1	Street Address 2
110 East 59th St., 4th Floor
City	State/Province/Country	ZIP/Postal Code
New York	NEW YORK	10022
State(s) of Solicitation (select all that apply) Check "All States" or check individual States X All States	Foreign/non-US

13. Offering and Sales Amounts

Total Offering Amount	$150,000,000	USD	or Indefinite
Total Amount Sold	$25,000,000	USD
Total Remaining to be Sold	$125,000,000	USD	or Indefinite

Clarification of Response (if Necessary):

14. Investors

Select if securities in the offering have been or may be sold to persons who do not qualify as accredited investors, and enter the number of such non-accredited investors who already have invested in the offering.

Regardless of whether securities in the offering have been or may be sold to persons who do not qualify as accredited investors, enter the total number of investors who already have invested in the offering:

38

15. Sales Commissions & Finder's Fees Expenses

Provide separately the amounts of sales commissions and finders fees expenses, if any. If the amount of an expenditure is not known, provide an estimate and check the box next to the amount.

Sales Commissions	$1,375,000	USD	X Estimate
Finders' Fees	$0	USD	Estimate

Clarification of Response (if Necessary):

16. Use of Proceeds

Provide the amount of the gross proceeds of the offering that has been or is proposed to be used for payments to any of the persons required to be named as executive officers, directors or promoters in response to Item 3 above. If the amount is unknown, provide an estimate and check the box next to the amount.

$0

USD

Estimate

Clarification of Response (if Necessary):

Signature and Submission

Please verify the information you have entered and review the Terms of Submission below before signing and clicking SUBMIT below to file this notice.

Terms of Submission

In submitting this notice, each issuer named above is:

• Notifying the SEC and/or each State in which this notice is filed of the offering of securities described and undertaking to furnish them, upon written request, in the accordance with applicable law, the information furnished to offerees.*

• Irrevocably appointing each of the Secretary of the SEC and, the Securities Administrator or other legally designated officer of the State in which the issuer maintains its principal place of business and any State in which this notice is filed, as its agents for service of process, and agreeing that these persons may accept service on its behalf, of any notice, process or pleading, and further agreeing that such service may be made by registered or certified mail, in any Federal or state action, administrative proceeding, or arbitration brought against the issuer in any place subject to the jurisdiction of the United States, if the action, proceeding or arbitration (a) arises out of any activity in connection with the offering of securities that is the subject of this notice, and (b) is founded, directly or indirectly, upon the provisions of: (i) the Securities Act of 1933, the Securities Exchange Act of 1934, the Trust Indenture Act of 1939, the Investment Company Act of 1940, or the Investment Advisers Act of 1940, or any rule or regulation under any of these statutes, or (ii) the laws of the State in which the issuer maintains its principal place of business or any State in which this notice is filed.

• Certifying that, if the issuer is claiming a Regulation D exemption for the offering, the issuer is not disqualified from relying on Rule 504 or Rule 506 for one of the reasons stated in Rule 504(b)(3) or Rule 506(d).

Each Issuer identified above has read this notice, knows the contents to be true, and has duly caused this notice to be signed on its behalf by the undersigned duly authorized person.

For signature, type in the signer's name or other letters or characters adopted or authorized as the signer's signature.

Issuer	Signature	Name of Signer	Title	Date
Gossamer Bio, Inc.	/s/ Bryan Giraudo	Bryan Giraudo	COO & CFO	2026-09-04

Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB number.

* This undertaking does not affect any limits Section 102(a) of the National Securities Markets Improvement Act of 1996 ("NSMIA") [Pub. L. No. 104-290, 110 Stat. 3416 (Oct. 11, 1996)] imposes on the ability of States to require information. As a result, if the securities that are the subject of this Form D are "covered securities" for purposes of NSMIA, whether in all instances or due to the nature of the offering that is the subject of this Form D, States cannot routinely require offering materials under this undertaking or otherwise and can require offering materials only to the extent NSMIA permits them to do so under NSMIA's preservation of their anti-fraud authority.