Gossamer Bio, Inc.
DE ˙ DB ˙ US38341P1021
0,17 € ↑0,02 (10,16%)
2026-06-05
DEL PRIS
SecurityDE:4GB / Gossamer Bio, Inc.
InstitutionCitadel Advisors Llc
ManagerKen Griffin
Latest Disclosed Ownership0 shares
Latest Disclosed Value $ 0
Citadel Advisors Llc ownership in 4GB / Gossamer Bio, Inc.

On May 15, 2026 - Citadel Advisors Llc filed a 13F-HR form disclosing ownership of 0 shares of Gossamer Bio, Inc. (DE:4GB) valued at $0 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 704,787 shares of Gossamer Bio, Inc.. This represents a change in shares of -100.00% during the quarter. The current value of the position is $0 USD.

Citadel Advisors Llc has a history of taking positions in derivatives of the underlying security (4GB) in the form of stock options. The firm currently holds call options representing 220,100 of underlying shares valued at $72,303 USD and put options representing 171,200 of underlying shares valued at $56,239 USD .

Note: prior versions of this page mistakenly stated that the share values represented the number of options, not the number of underlying shares. For more information on the data backing these reports, please see the SEC document Frequently Asked Questions About Form 13F.

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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Institutional Put/Call Ratios
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In addition to reporting standard equity and debt issues, institutions with more than 100MM assets under management must also disclose their put and call option holdings. Since put options generally indicate negative sentiment, and call options indicate positive sentiment, we can get a sense of the overall institutional sentiment by plotting the ratio of puts to calls. The chart to the right plots the historical put/call ratio for this instrument.

Using Put/Call Ratio as an indicator of investor sentiment overcomes one of the key deficiencies of using total institutional ownership, which is that a significant amount of assets under management are invested passively to track indices. Passively-managed funds do not typically buy options, so the put/call ratio indicator more closely tracks the sentiment of actively-managed funds.

DE:4GB / Gossamer Bio, Inc. Historical Put/Call Ratio
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)
2026-05-15 2026-03-31 13F GOSSAMER BIO COM 38341P102 0 -704,787 -100.00 0 -100.00
2026-02-17 2025-12-31 13F GOSSAMER BIO COM 38341P102 704,787 -1,579,429 -69.15 2,185 -63.64 0.0003
2025-11-14 2025-09-30 13F GOSSAMER BIO COM 38341P102 2,284,216 1,516,655 197.59 6,007 536.33 0.0009
2025-08-14 2025-06-30 13F GOSSAMER BIO COM 38341P102 767,561 610,629 389.10 944 448.84 0.0002
2025-05-15 2025-03-31 13F GOSSAMER BIO COM 38341P102 156,932 16,925 12.09 173 36.51 0.0000
2025-02-14 2024-12-31 13F GOSSAMER BIO COM 38341P102 140,007 -900,046 -86.54 127 -87.71 0.0000
2024-11-14 2024-09-30 13F GOSSAMER BIO COM 38341P102 1,040,053 -3,053,783 -74.59 1,026 -72.21 0.0002
2024-08-14 2024-06-30 13F GOSSAMER BIO COM 38341P102 4,093,836 219,110 5.65 3,688 -19.34 0.0007
2024-05-15 2024-03-31 13F GOSSAMER BIO COM 38341P102 3,874,726 -2,265,506 -36.90 4,572 -18.39 0.0009
2024-02-14 2023-12-31 13F GOSSAMER BIO COM 38341P102 6,140,232 -27,911 -0.45 5,603 9.07 0.0011
2023-11-14 2023-09-30 13F GOSSAMER BIO COM 38341P102 6,168,143 4,741,674 332.41 5,137 200.18 0.0011
2023-08-14 2023-06-30 13F GOSSAMER BIO COM 38341P102 1,426,469 -1,368,248 -48.96 1,712 -51.41 0.0004
2023-05-15 2023-03-31 13F GOSSAMER BIO COM 38341P102 2,794,717 2,794,717 3,521 0.0008
2023-02-14 2022-12-31 13F GOSSAMER BIO COM 38341P102 0 -731,264 -100.00 0 -100.00
2022-11-14 2022-09-30 13F GOSSAMER BIO COM 38341P102 731,264 -1,551,585 -67.97 8,761 -54.15 0.0020
2022-08-15 2022-06-30 13F GOSSAMER BIO COM 38341P102 2,282,849 138,538 6.46 19,108 2.66 0.0049
2022-05-16 2022-03-31 13F GOSSAMER BIO COM 38341P102 2,144,311 268,560 14.32 18,613 -12.26 0.0038
2022-02-14 2021-12-31 13F GOSSAMER BIO COM 38341P102 1,875,751 287,800 18.12 21,214 6.28 0.0043
2021-11-15 2021-09-30 13F GOSSAMER BIO Cmn 38341P102 1,587,951 1,572,150 9,949.69 19,960 15,493.75 0.0041
2021-08-16 2021-06-30 13F GOSSAMER BIO COM 38341P102 15,801 -564,995 -97.28 128 -97.62 0.0000
2021-05-21 2021-03-31 13F/A-1 GOSSAMER BIO COM 38341P102 580,796 -189,962 -24.65 5,372 -27.93 0.0013
2021-05-17 2021-03-31 13F GOSSAMER BIO COM 38341P102 580,796 -189,962 5,372 0.0013
2021-02-16 2020-12-31 13F GOSSAMER BIO COM 38341P102 770,758 691,286 869.85 7,454 655.98 0.0019
2020-11-16 2020-09-30 13F GOSSAMER BIO COM 38341P102 79,472 33,286 72.07 986 64.33 0.0003
2020-08-14 2020-06-30 13F GOSSAMER BIO Cmn 38341P102 46,186 -268,266 -85.31 600 -81.20 0.0002
2020-05-15 2020-03-31 13F GOSSAMER BIO Cmn 38341P102 314,452 272,828 655.46 3,191 390.92 0.0014
2020-02-14 2019-12-31 13F GOSSAMER BIO Cmn 38341P102 41,624 -881,320 -95.49 650 -95.81 0.0003
2019-11-14 2019-09-30 13F GOSSAMER BIO Cmn 38341P102 922,944 -3,978 -0.43 15,497 -24.63 0.0073
2019-08-14 2019-06-30 13F GOSSAMER BIO Cmn 38341P102 926,922 -45,651 -4.69 20,560 -2.45 0.0094
2019-05-15 2019-03-31 13F GOSSAMER BIO Cmn 38341P102 972,573 972,573 21,076 0.0105
Disclosed Call Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share
Price
Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2026-05-15 2026-03-31 13F GOSSAMER BIO COM Call 220,100 -68.15 72 -96.64 n/a n/a n/a
2026-02-17 2025-12-31 13F GOSSAMER BIO COM Call 691,100 142.75 2,142 186.36 n/a n/a n/a
2025-11-14 2025-09-30 13F GOSSAMER BIO COM Call 284,700 230.66 749 612.38 n/a n/a n/a
2025-08-14 2025-06-30 13F GOSSAMER BIO COM Call 86,100 25.88 106 40.00 n/a n/a n/a
2025-05-15 2025-03-31 13F GOSSAMER BIO COM Call 68,400 -44.16 75 -31.82 n/a n/a n/a
2025-02-14 2024-12-31 13F GOSSAMER BIO COM Call 122,500 29.36 111 18.28 n/a n/a n/a
2024-11-14 2024-09-30 13F GOSSAMER BIO COM Call 94,700 -15.07 93 -7.00 n/a n/a n/a
2024-08-14 2024-06-30 13F GOSSAMER BIO COM Call 111,500 12.74 100 -13.79 n/a n/a n/a
2024-05-15 2024-03-31 13F GOSSAMER BIO COM Call 98,900 -10.42 117 16.00 n/a n/a n/a
2024-02-14 2023-12-31 13F GOSSAMER BIO COM Call 110,400 -2.73 101 6.38 n/a n/a n/a
2023-11-14 2023-09-30 13F GOSSAMER BIO COM Call 113,500 46.07 95 1.08 n/a n/a n/a
2023-08-14 2023-06-30 13F GOSSAMER BIO COM Call 77,700 59.55 93 52.46 n/a n/a n/a
2023-05-15 2023-03-31 13F GOSSAMER BIO COM Call 48,700 -69.64 61 -82.47 n/a n/a n/a
2023-02-14 2022-12-31 13F GOSSAMER BIO COM Call 160,400 -46.57 348 -90.32 n/a n/a n/a
2022-11-14 2022-09-30 13F GOSSAMER BIO COM Call 300,200 -10.76 3,596 27.70 n/a n/a n/a
2022-08-15 2022-06-30 13F GOSSAMER BIO COM Call 336,400 -32.05 2,816 -34.47 n/a n/a n/a
2022-05-16 2022-03-31 13F GOSSAMER BIO COM Call 495,100 2,140.27 4,297 1,618.80 n/a n/a n/a
2022-02-14 2021-12-31 13F GOSSAMER BIO COM Call 22,100 23.46 250 11.11 n/a n/a n/a
2021-11-15 2021-09-30 13F GOSSAMER BIO Cmn Call 17,900 -13.11 225 34.73 n/a n/a n/a
2021-08-16 2021-06-30 13F GOSSAMER BIO COM Call 20,600 -51.53 167 -57.51 n/a n/a n/a
2021-05-21 2021-03-31 13F/A GOSSAMER BIO COM Call 42,500 91.44 393 82.79 n/a n/a n/a
2021-05-17 2021-03-31 13F GOSSAMER BIO COM Call 42,500 393 n/a n/a n/a
2021-02-16 2020-12-31 13F GOSSAMER BIO COM Call 22,200 215 n/a n/a n/a
2020-11-16 2020-09-30 13F GOSSAMER BIO Cmn Call 0 -100.00 0 -100.00 n/a n/a n/a
2020-08-14 2020-06-30 13F GOSSAMER BIO Cmn Call 28,400 134.71 369 200.00 n/a n/a n/a
2020-05-15 2020-03-31 13F GOSSAMER BIO Cmn Call 12,100 -30.86 123 -55.11 n/a n/a n/a
2020-02-14 2019-12-31 13F GOSSAMER BIO Cmn Call 17,500 2.34 274 -4.53 n/a n/a n/a
2019-11-14 2019-09-30 13F GOSSAMER BIO Cmn Call 17,100 287 n/a n/a n/a
Disclosed Put Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share Price Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2026-05-15 2026-03-31 13F GOSSAMER BIO COM Put 171,200 -0.06 56 -89.45 n/a n/a n/a
2026-02-17 2025-12-31 13F GOSSAMER BIO COM Put 171,300 92.26 531 126.92 n/a n/a n/a
2025-11-14 2025-09-30 13F GOSSAMER BIO COM Put 89,100 55.23 234 234.29 n/a n/a n/a
2025-08-14 2025-06-30 13F GOSSAMER BIO COM Put 57,400 -0.69 71 11.11 n/a n/a n/a
2025-05-15 2025-03-31 13F GOSSAMER BIO COM Put 57,800 -28.73 64 -13.70 n/a n/a n/a
2025-02-14 2024-12-31 13F GOSSAMER BIO COM Put 81,100 55.07 73 43.14 n/a n/a n/a
2024-11-14 2024-09-30 13F GOSSAMER BIO COM Put 52,300 -10.14 52 -1.92 n/a n/a n/a
2024-08-14 2024-06-30 13F GOSSAMER BIO COM Put 58,200 646.15 52 477.78 n/a n/a n/a
2024-05-15 2024-03-31 13F GOSSAMER BIO COM Put 7,800 41.82 9 80.00 n/a n/a n/a
2024-02-14 2023-12-31 13F GOSSAMER BIO COM Put 5,500 -11.29 5 0.00 n/a n/a n/a
2023-11-14 2023-09-30 13F GOSSAMER BIO COM Put 6,200 -38.00 5 -58.33 n/a n/a n/a
2023-08-14 2023-06-30 13F GOSSAMER BIO COM Put 10,000 -75.79 12 -76.92 n/a n/a n/a
2023-05-15 2023-03-31 13F GOSSAMER BIO COM Put 41,300 -60.44 52 -76.99 n/a n/a n/a
2023-02-14 2022-12-31 13F GOSSAMER BIO COM Put 104,400 303.09 227 -27.10 n/a n/a n/a
2022-11-14 2022-09-30 13F GOSSAMER BIO COM Put 25,900 310 n/a n/a n/a
2022-08-15 2022-06-30 13F GOSSAMER BIO COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2022-05-16 2022-03-31 13F GOSSAMER BIO COM Put 36,200 136.60 314 81.50 n/a n/a n/a
2022-02-14 2021-12-31 13F GOSSAMER BIO COM Put 15,300 173 n/a n/a n/a
2022-03-11 2021-09-30 13F/A GOSSAMER BIO COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2021-11-15 2021-09-30 13F GOSSAMER BIO COM Put 0 0 n/a n/a n/a
2021-08-16 2021-06-30 13F GOSSAMER BIO COM Put 259,700 -0.15 2,109 -12.34 n/a n/a n/a
2021-05-21 2021-03-31 13F/A GOSSAMER BIO COM Put 260,100 588.10 2,406 557.38 n/a n/a n/a
2021-05-17 2021-03-31 13F GOSSAMER BIO COM Put 260,100 2,406 n/a n/a n/a
2021-02-16 2020-12-31 13F GOSSAMER BIO COM Put 37,800 23.53 366 -3.68 n/a n/a n/a
2020-11-16 2020-09-30 13F GOSSAMER BIO COM Put 30,600 140.94 380 130.30 n/a n/a n/a
2020-08-14 2020-06-30 13F GOSSAMER BIO Cmn Put 12,700 7.63 165 37.50 n/a n/a n/a
2020-05-15 2020-03-31 13F GOSSAMER BIO Cmn Put 11,800 -80.66 120 -87.41 n/a n/a n/a
2020-02-14 2019-12-31 13F GOSSAMER BIO Cmn Put 61,000 -77.64 953 -79.19 n/a n/a n/a
2019-11-14 2019-09-30 13F GOSSAMER BIO Cmn Put 272,800 4,580 n/a n/a n/a
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.