Gossamer Bio, Inc.
US ˙ NasdaqGS ˙ US38341P1021

SecurityGOSS / Gossamer Bio, Inc.
InstitutionCitigroup Inc
Latest Disclosed Ownership17,754 shares
Latest Disclosed Value $ 5,832
Citigroup Inc reports 63.92% decrease in ownership of GOSS / Gossamer Bio, Inc.

On May 11, 2026 - Citigroup Inc filed a 13F-HR form disclosing ownership of 17,754 shares of Gossamer Bio, Inc. (US:GOSS) valued at $5,832 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 49,212 shares of Gossamer Bio, Inc.. This represents a change in shares of -63.92% during the quarter. The current value of the position is $3,343 USD.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-05-11 2026-03-31 13F GOSSAMER BIO COM 38341P102 17,754 -31,458 -63.92 6 -96.71 0.0000
2026-02-13 2025-12-31 13F GOSSAMER BIO COM 38341P102 49,212 19,197 63.96 153 94.87 0.0001
2025-11-10 2025-09-30 13F GOSSAMER BIO COM 38341P102 30,015 -37,419 -55.49 79 -4.88 0.0000
2025-08-11 2025-06-30 13F GOSSAMER BIO COM 38341P102 67,434 56,756 531.52 83 645.45 0.0000
2025-05-12 2025-03-31 13F GOSSAMER BIO COM 38341P102 10,678 10,675 355,833.33 12 0.0000
2025-02-12 2024-12-31 13F GOSSAMER BIO COM 38341P102 3 -657,835 -100.00 0 -100.00 0.0000
2024-11-12 2024-09-30 13F GOSSAMER BIO COM 38341P102 657,838 157,835 31.57 649 44.00 0.0004
2024-08-12 2024-06-30 13F GOSSAMER BIO COM 38341P102 500,003 -1,787,777 -78.14 450 -83.33 0.0003
2024-05-10 2024-03-31 13F GOSSAMER BIO COM 38341P102 2,287,780 582,344 34.15 2,700 73.46 0.0018
2024-02-09 2023-12-31 13F GOSSAMER BIO COM 38341P102 1,705,436 1,508,704 766.88 1,556 854.60 0.0011
2023-12-06 2023-09-30 13F/A-1 GOSSAMER BIO COM 38341P102 196,732 194,768 9,916.90 164 8,050.00 0.0001
2023-11-09 2023-09-30 13F GOSSAMER BIO COM 38341P102 196,732 194,768 164 0.0000
2023-08-10 2023-06-30 13F GOSSAMER BIO COM 38341P102 1,964 564 40.29 2 100.00 0.0000
2023-05-11 2023-03-31 13F GOSSAMER BIO COM 38341P102 1,400 -1,204,145 -99.88 2 -99.96 0.0000
2023-02-09 2022-12-31 13F GOSSAMER BIO COM 38341P102 1,205,545 130,448 12.13 2,616 -79.69 0.0021
2022-11-10 2022-09-30 13F GOSSAMER BIO COM 38341P102 1,075,097 200,311 22.90 12,880 75.91 0.0092
2022-08-10 2022-06-30 13F GOSSAMER BIO COM 38341P102 874,786 808,377 1,217.27 7,322 1,171.18 0.0054
2022-05-12 2022-03-31 13F GOSSAMER BIO COM 38341P102 66,409 -86,376 -56.53 576 -66.67 0.0004
2022-02-10 2021-12-31 13F GOSSAMER BIO COM 38341P102 152,785 -31,993 -17.31 1,728 -25.61 0.0009
2021-11-10 2021-09-30 13F GOSSAMER BIO COM 38341P102 184,778 6,660 3.74 2,323 60.65 0.0014
2021-08-10 2021-06-30 13F GOSSAMER BIO COM 38341P102 178,118 -39,515 -18.16 1,446 -28.17 0.0009
2021-05-13 2021-03-31 13F GOSSAMER BIO COM 38341P102 217,633 200,077 1,139.65 2,013 1,084.12 0.0013
2021-02-11 2020-12-31 13F GOSSAMER BIO COM 38341P102 17,556 10,889 163.33 170 104.82 0.0001
2020-11-12 2020-09-30 13F GOSSAMER BIO COM 38341P102 6,667 -29,959 -81.80 83 -82.56 0.0001
2020-08-12 2020-06-30 13F GOSSAMER BIO COM 38341P102 36,626 1,068 3.00 476 31.86 0.0004
2020-05-12 2020-03-31 13F GOSSAMER BIO COM 38341P102 35,558 -3,278 -8.44 361 -40.53 0.0003
2020-02-12 2019-12-31 13F GOSSAMER BIO COM 38341P102 38,836 36,845 1,850.58 607 1,739.39 0.0004
2019-11-08 2019-09-30 13F GOSSAMER BIO COM 38341P102 1,991 -4,288 -68.29 33 -76.43 0.0000
2019-08-12 2019-06-30 13F GOSSAMER BIO COM 38341P102 6,279 3,218 105.13 140 112.12 0.0001
2019-05-13 2019-03-31 13F GOSSAMER BIO COM 38341P102 3,061 3,061 66 0.0001
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.