Richard Aranda - 19 Mar 2026 Form 4 Insider Report for Gossamer Bio, Inc. (GOSS)

Reporting relationship
Chief Medical Officer
Issuer ticker
GOSS
Reported as of
19 Mar 2026
Net transaction value
$0
Source evidence Original filing metadata and source links for verification. 4 source fields
SEC form
4
Accepted by SEC
20 Mar 2026, 16:22:00 UTC
Prior SEC filing
05 Jan 2026
Source filing
View source filing
Reporting owner 1 detail
Reporting owner signature
/s/ Jeff Boerneke, Attorney-in-Fact

Key filing fact

Richard Aranda filed Form 4 for Gossamer Bio, Inc. (GOSS) on 20 Mar 2026.

Key facts

  • This page summarizes Richard Aranda's Form 4 filing for Gossamer Bio, Inc. (GOSS).
  • 24 reported transactions and 24 derivative rows are listed below.
  • Accepted by SEC: 20 Mar 2026, 16:22.

Change

  • Previous filing in this sequence was filed on 05 Jan 2026.
  • Current net transaction value: $0.

Research use

  • This tells you what this filing adds before you inspect full transaction and derivative tables.
  • You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001867872 Primary reporting owner

Aranda Richard

Relationship
Chief Medical Officer
Address
3115 MERRYFIELD ROW, SUITE 120, SAN DIEGO
Signature
/s/ Jeff Boerneke, Attorney-in-Fact
Signature date
20 Mar 2026

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

GOSS transaction Derivative

Stock Option (Right to Buy)

Disposed to Issuer

Transaction value
Shares
-562,500
Change %
-100%
Price
Shares after
0
Date
19 Mar 2026
Ownership
Direct
Underlying class
Common Stock
Underlying amount
562,500
Exercise price
$2.88
Footnotes
F1, F2
GOSS transaction Derivative

Stock Option (Right to Buy)

Disposed to Issuer

Transaction value
Shares
-572,000
Change %
-100%
Price
Shares after
0
Date
19 Mar 2026
Ownership
Direct
Underlying class
Common Stock
Underlying amount
572,000
Exercise price
$1.13
Footnotes
F1, F2
GOSS transaction Derivative

Stock Option (Right to Buy)

Disposed to Issuer

Transaction value
Shares
-487,500
Change %
-100%
Price
Shares after
0
Date
19 Mar 2026
Ownership
Direct
Underlying class
Common Stock
Underlying amount
487,500
Exercise price
$0.9700
Footnotes
F1, F2
GOSS transaction Derivative

Stock Option (Right to Buy)

Disposed to Issuer

Transaction value
Shares
-162,500
Change %
-100%
Price
Shares after
0
Date
19 Mar 2026
Ownership
Direct
Underlying class
Common Stock
Underlying amount
162,500
Exercise price
$0.8380
Footnotes
F1, F2
GOSS transaction Derivative

Stock Option (Right to Buy)

Disposed to Issuer

Transaction value
Shares
-157,500
Change %
-100%
Price
Shares after
0
Date
19 Mar 2026
Ownership
Direct
Underlying class
Common Stock
Underlying amount
157,500
Exercise price
$1.21
Footnotes
F1, F2
GOSS transaction Derivative

Stock Option (Right to Buy)

Disposed to Issuer

Transaction value
Shares
-157,500
Change %
-100%
Price
Shares after
0
Date
19 Mar 2026
Ownership
Direct
Underlying class
Common Stock
Underlying amount
157,500
Exercise price
$2.16
Footnotes
F1, F2
GOSS transaction Derivative

Stock Option (Right to Buy)

Disposed to Issuer

Transaction value
Shares
-126,667
Change %
-100%
Price
Shares after
0
Date
19 Mar 2026
Ownership
Direct
Underlying class
Common Stock
Underlying amount
126,667
Exercise price
$1.36
Footnotes
F1, F2
GOSS transaction Derivative

Stock Option (Right to Buy)

Disposed to Issuer

Transaction value
Shares
-20,000
Change %
-100%
Price
Shares after
0
Date
19 Mar 2026
Ownership
Direct
Underlying class
Common Stock
Underlying amount
20,000
Exercise price
$1.36
Footnotes
F1, F2
GOSS transaction Derivative

Stock Option (Right to Buy)

Disposed to Issuer

Transaction value
Shares
-40,000
Change %
-100%
Price
Shares after
0
Date
19 Mar 2026
Ownership
Direct
Underlying class
Common Stock
Underlying amount
40,000
Exercise price
$1.36
Footnotes
F1, F2
GOSS transaction Derivative

Stock Option (Right to Buy)

Disposed to Issuer

Transaction value
Shares
-22,784
Change %
-100%
Price
Shares after
0
Date
19 Mar 2026
Ownership
Direct
Underlying class
Common Stock
Underlying amount
22,784
Exercise price
$1.36
Footnotes
F1, F2
GOSS transaction Derivative

Stock Option (Right to Buy)

Disposed to Issuer

Transaction value
Shares
-9,167
Change %
-100%
Price
Shares after
0
Date
19 Mar 2026
Ownership
Direct
Underlying class
Common Stock
Underlying amount
9,167
Exercise price
$1.36
Footnotes
F1, F2
GOSS transaction Derivative

Stock Option (Right to Buy)

Disposed to Issuer

Transaction value
Shares
-30,000
Change %
-100%
Price
Shares after
0
Date
19 Mar 2026
Ownership
Direct
Underlying class
Common Stock
Underlying amount
30,000
Exercise price
$1.36
Footnotes
F1, F2
GOSS transaction Derivative

Stock Option (Right to Buy)

Award

Transaction value
Shares
+562,500
Change %
Price
Shares after
562,500
Date
19 Mar 2026
Ownership
Direct
Underlying class
Common Stock
Underlying amount
562,500
Exercise price
$0.4500
Footnotes
F1, F2
GOSS transaction Derivative

Stock Option (Right to Buy)

Award

Transaction value
Shares
+572,000
Change %
Price
Shares after
572,000
Date
19 Mar 2026
Ownership
Direct
Underlying class
Common Stock
Underlying amount
572,000
Exercise price
$0.4500
Footnotes
F1, F2
GOSS transaction Derivative

Stock Option (Right to Buy)

Award

Transaction value
Shares
+487,500
Change %
Price
Shares after
487,500
Date
19 Mar 2026
Ownership
Direct
Underlying class
Common Stock
Underlying amount
487,500
Exercise price
$0.4500
Footnotes
F1, F2
GOSS transaction Derivative

Stock Option (Right to Buy)

Award

Transaction value
Shares
+162,500
Change %
Price
Shares after
162,500
Date
19 Mar 2026
Ownership
Direct
Underlying class
Common Stock
Underlying amount
162,500
Exercise price
$0.4500
Footnotes
F1, F2
GOSS transaction Derivative

Stock Option (Right to Buy)

Award

Transaction value
Shares
+157,500
Change %
Price
Shares after
157,500
Date
19 Mar 2026
Ownership
Direct
Underlying class
Common Stock
Underlying amount
157,500
Exercise price
$0.4500
Footnotes
F1, F2
GOSS transaction Derivative

Stock Option (Right to Buy)

Award

Transaction value
Shares
+157,500
Change %
Price
Shares after
157,500
Date
19 Mar 2026
Ownership
Direct
Underlying class
Common Stock
Underlying amount
157,500
Exercise price
$0.4500
Footnotes
F1, F2
GOSS transaction Derivative

Stock Option (Right to Buy)

Award

Transaction value
Shares
+126,667
Change %
Price
Shares after
126,667
Date
19 Mar 2026
Ownership
Direct
Underlying class
Common Stock
Underlying amount
126,667
Exercise price
$0.4500
Footnotes
F1, F2
GOSS transaction Derivative

Stock Option (Right to Buy)

Award

Transaction value
Shares
+20,000
Change %
Price
Shares after
20,000
Date
19 Mar 2026
Ownership
Direct
Underlying class
Common Stock
Underlying amount
20,000
Exercise price
$0.4500
Footnotes
F1, F2
GOSS transaction Derivative

Stock Option (Right to Buy)

Award

Transaction value
Shares
+40,000
Change %
Price
Shares after
40,000
Date
19 Mar 2026
Ownership
Direct
Underlying class
Common Stock
Underlying amount
40,000
Exercise price
$0.4500
Footnotes
F1, F2
GOSS transaction Derivative

Stock Option (Right to Buy)

Award

Transaction value
Shares
+22,784
Change %
Price
Shares after
22,784
Date
19 Mar 2026
Ownership
Direct
Underlying class
Common Stock
Underlying amount
22,784
Exercise price
$0.4500
Footnotes
F1, F2
GOSS transaction Derivative

Stock Option (Right to Buy)

Award

Transaction value
Shares
+9,167
Change %
Price
Shares after
9,167
Date
19 Mar 2026
Ownership
Direct
Underlying class
Common Stock
Underlying amount
9,167
Exercise price
$0.4500
Footnotes
F1, F2
GOSS transaction Derivative

Stock Option (Right to Buy)

Award

Transaction value
Shares
+30,000
Change %
Price
Shares after
30,000
Date
19 Mar 2026
Ownership
Direct
Underlying class
Common Stock
Underlying amount
30,000
Exercise price
$0.4500
Footnotes
F1, F2
* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 2 footnotes

Footnote F1

Effective as of March 19, 2026 (the "Repricing Date"), the Issuer approved a one-time repricing of certain outstanding stock options (the "Repriced Options") granted under the Issuer's 2019 Incentive Award Plan (the "2019 Plan"), which reduced the per share exercise price of each Repriced Option to $0.45 (the "Option Repricing"). Except as modified by the Option Repricing, all other terms and conditions of the Repriced Options, including, without limitation, any provisions with respect to vesting and term of the Repriced Options, remain in full force and effect.

Footnote F2

This stock option award was issued pursuant to the 2019 Plan and becomes exercisable in accordance with the vesting schedule specified in the award agreement and as previously reported on applicable Form 4, subject to the Reporting Person's continued service with the Issuer as of the applicable vesting date.

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