SELLAS Life Sciences Group, Inc.
US ˙ NasdaqCM ˙ US81642T2096

SecuritySLS / SELLAS Life Sciences Group, Inc.
InstitutionSimplex Trading, Llc
Latest Disclosed Ownership295,162 shares
Latest Disclosed Value $ 1,248,535
Simplex Trading, Llc ownership in SLS / SELLAS Life Sciences Group, Inc.

On May 14, 2026 - Simplex Trading, Llc filed a 13F-HR form disclosing ownership of 295,162 shares of SELLAS Life Sciences Group, Inc. (US:SLS) valued at $1,248,535 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 2, 2023 disclosing 0 shares of SELLAS Life Sciences Group, Inc.. The current value of the position is $2,417,377 USD.

Simplex Trading, Llc has a history of taking positions in derivatives of the underlying security (SLS) in the form of stock options. The firm currently holds call options representing 1,207,400 of underlying shares valued at $5,107,302 USD and put options representing 153,400 of underlying shares valued at $648,882 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.

SLS / SELLAS Life Sciences Group, 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)
2026-05-14 2026-03-31 13F SELLAS LIFE SCIENCES GROUP I COM 81642T209 295,162 295,162 1,249 0.0008
2023-02-02 2022-12-31 13F SELLAS LIFE SCIENCES GROUP I COM 81642T209 0 -1,315 -100.00 0 -100.00
2022-11-04 2022-09-30 13F SELLAS LIFE SCIENCES GROUP I COM 81642T209 1,315 1,315 2 0.0000
2022-08-03 2022-06-30 13F SELLAS LIFE SCIENCES GROUP I COM 81642T209 0 -6,912 -100.00 0 -100.00
2022-05-02 2022-03-31 13F SELLAS LIFE SCIENCES GROUP I COM 81642T209 6,912 -36 -0.52 46 21.05 0.0000
2022-02-23 2021-12-31 13F/A-1 SELLAS LIFE SCIENCES GROUP I COM 81642T209 6,948 6,948 38 0.0000
2021-04-26 2021-03-31 13F SELLAS LIFE SCIENCES GROUP I COM 81642T209 0 -16 -100.00 0 0.0000
2021-02-02 2020-12-31 13F SELLAS LIFE SCIENCES GROUP I COM 81642T209 16 16 0 0.0000
2017-10-25 2017-09-30 13F GALENA BIOPHARMA COM 363256504 0 -1,000 -100.00 0 0.0000
2017-07-12 2017-06-30 13F GALENA BIOPHARMA COM 363256504 1,000 1,000 0 0.0000
2017-01-11 2016-12-31 13F GALENA BIOPHARMA COM 363256108 0 -18,771 -100.00 0 -100.00
2016-10-07 2016-09-30 13F GALENA BIOPHARMA COM 363256108 18,771 -26,500 -58.54 6 -71.43 0.0004
2016-07-18 2016-06-30 13F GALENA BIOPHARMA COM 363256108 45,271 38,369 555.91 21 133.33 0.0014
2016-04-14 2016-03-31 13F GALENA BIOPHARMA COM 363256108 6,902 1,710 32.94 9 28.57 0.0007
2016-01-20 2015-12-31 13F GALENA BIOPHARMA COM 363256108 5,192 4,000 335.57 7 600.00 0.0005
2015-10-08 2015-09-30 13F GALENA BIOPHARMA COM 363256108 1,192 1,192 1 0.0001
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
(%)
2026-05-14 2026-03-31 13F SELLAS LIFE SCIENCES GROUP I CALL Call 1,207,400 5,107 n/a n/a n/a
2026-02-11 2025-12-31 13F SELLAS LIFE SCIENCES GROUP I CALL Call 0 -100.00 0 -100.00 n/a n/a n/a
2025-11-12 2025-09-30 13F SELLAS LIFE SCIENCES GROUP I CALL Call 1,617,700 93.74 3 100.00 n/a n/a n/a
2025-08-05 2025-06-30 13F SELLAS LIFE SCIENCES GROUP I CALL Call 835,000 74.83 2 n/a n/a n/a
2025-05-12 2025-03-31 13F SELLAS LIFE SCIENCES GROUP I CALL Call 477,600 -8.47 1 n/a n/a n/a
2025-02-11 2024-12-31 13F SELLAS LIFE SCIENCES GROUP I CALL Call 521,800 -22.07 1 n/a n/a n/a
2024-11-08 2024-09-30 13F SELLAS LIFE SCIENCES GROUP I CALL Call 669,600 56.38 1 n/a n/a n/a
2024-07-25 2024-06-30 13F SELLAS LIFE SCIENCES GROUP I CALL Call 428,200 -1.11 1 n/a n/a n/a
2024-04-25 2024-03-31 13F SELLAS LIFE SCIENCES GROUP I CALL Call 433,000 25.36 0 n/a n/a n/a
2024-02-02 2023-12-31 13F SELLAS LIFE SCIENCES GROUP I CALL Call 345,400 55.03 0 n/a n/a n/a
2023-11-01 2023-09-30 13F SELLAS LIFE SCIENCES GROUP I CALL Call 222,800 -20.17 0 n/a n/a n/a
2023-08-04 2023-06-30 13F SELLAS LIFE SCIENCES GROUP I CALL Call 279,100 -10.72 0 n/a n/a n/a
2023-04-27 2023-03-31 13F SELLAS LIFE SCIENCES GROUP I CALL Call 312,600 177.13 0 n/a n/a n/a
2023-02-02 2022-12-31 13F SELLAS LIFE SCIENCES GROUP I CALL Call 112,800 278.52 0 -100.00 n/a n/a n/a
2022-11-04 2022-09-30 13F SELLAS LIFE SCIENCES GROUP I CALL Call 29,800 2.05 60 -7.69 n/a n/a n/a
2022-08-03 2022-06-30 13F SELLAS LIFE SCIENCES GROUP I CALL Call 29,200 189.11 65 -2.99 n/a n/a n/a
2022-05-02 2022-03-31 13F SELLAS LIFE SCIENCES GROUP I CALL Call 10,100 -79.13 67 -74.91 n/a n/a n/a
2022-02-23 2021-12-31 13F/A SELLAS LIFE SCIENCES GROUP I CALL Call 48,400 -49.64 267 -70.20 n/a n/a n/a
2022-02-04 2021-12-31 13F SELLAS LIFE SCIENCES GROUP I CALL Call 96,100 896 n/a n/a n/a
2021-10-28 2021-09-30 13F SELLAS LIFE SCIENCES GROUP I CALL Call 96,100 -5.97 896 -20.99 n/a n/a n/a
2021-08-12 2021-06-30 13F SELLAS LIFE SCIENCES GROUP I CALL Call 102,200 20,972.16 1,134 173.91 n/a n/a n/a
2021-04-26 2021-03-31 13F SELLAS LIFE SCIENCES GROUP I CALL Call 485 432.97 414 696.15 n/a n/a n/a
2021-02-02 2020-12-31 13F SELLAS LIFE SCIENCES GROUP I CALL Call 91 52 n/a n/a n/a
2018-04-26 2018-03-31 13F GALENA BIOPHARMA CALL Call 0 -100.00 0 -100.00 n/a n/a n/a
2018-01-10 2017-12-31 13F GALENA BIOPHARMA CALL Call 630 -1.87 1 0.00 n/a n/a n/a
2017-10-25 2017-09-30 13F GALENA BIOPHARMA CALL Call 642 -3.75 1 0.00 n/a n/a n/a
2017-07-12 2017-06-30 13F GALENA BIOPHARMA CALL Call 667 -2.77 1 -50.00 n/a n/a n/a
2017-04-21 2017-03-31 13F GALENA BIOPHARMA CALL Call 686 -39.24 2 -66.67 n/a n/a n/a
2017-01-11 2016-12-31 13F GALENA BIOPHARMA CALL Call 1,129 -16.56 6 50.00 n/a n/a n/a
2016-10-07 2016-09-30 13F GALENA BIOPHARMA CALL Call 1,353 -24.24 4 -42.86 n/a n/a n/a
2016-07-18 2016-06-30 13F GALENA BIOPHARMA CALL Call 1,786 171.02 7 -77.42 n/a n/a n/a
2016-04-14 2016-03-31 13F GALENA BIOPHARMA CALL Call 659 153.46 31 3,000.00 n/a n/a n/a
2016-01-20 2015-12-31 13F GALENA BIOPHARMA CALL Call 260 36.84 1 -50.00 n/a n/a n/a
2015-10-08 2015-09-30 13F GALENA BIOPHARMA CALL Call 190 4.97 2 0.00 n/a n/a n/a
2015-07-08 2015-06-30 13F GALENA BIOPHARMA CALL Call 181 4.62 2 100.00 n/a n/a n/a
2015-04-21 2015-03-31 13F GALENA BIOPHARMA CALL Call 173 -26.69 1 -50.00 n/a n/a n/a
2015-03-04 2014-12-31 13F GALENA BIOPHARMA CALL Call 236 2 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
(%)
2026-05-14 2026-03-31 13F SELLAS LIFE SCIENCES GROUP I PUT Put 153,400 649 n/a n/a n/a
2026-02-11 2025-12-31 13F SELLAS LIFE SCIENCES GROUP I PUT Put 0 -100.00 0 n/a n/a n/a
2025-11-12 2025-09-30 13F SELLAS LIFE SCIENCES GROUP I PUT Put 49,400 2.28 0 n/a n/a n/a
2025-08-05 2025-06-30 13F SELLAS LIFE SCIENCES GROUP I PUT Put 48,300 48,200.00 0 n/a n/a n/a
2025-05-12 2025-03-31 13F SELLAS LIFE SCIENCES GROUP I PUT Put 100 -99.94 0 n/a n/a n/a
2025-02-11 2024-12-31 13F SELLAS LIFE SCIENCES GROUP I PUT Put 157,400 0 n/a n/a n/a
2024-11-08 2024-09-30 13F SELLAS LIFE SCIENCES GROUP I PUT Put 0 -100.00 0 n/a n/a n/a
2024-07-25 2024-06-30 13F SELLAS LIFE SCIENCES GROUP I PUT Put 3,400 30.77 0 n/a n/a n/a
2024-04-25 2024-03-31 13F SELLAS LIFE SCIENCES GROUP I PUT Put 2,600 2,500.00 0 n/a n/a n/a
2024-02-02 2023-12-31 13F SELLAS LIFE SCIENCES GROUP I PUT Put 100 -95.24 0 n/a n/a n/a
2023-11-01 2023-09-30 13F SELLAS LIFE SCIENCES GROUP I PUT Put 2,100 0.00 0 n/a n/a n/a
2023-08-04 2023-06-30 13F SELLAS LIFE SCIENCES GROUP I PUT Put 2,100 -4.55 0 n/a n/a n/a
2023-04-27 2023-03-31 13F SELLAS LIFE SCIENCES GROUP I PUT Put 2,200 83.33 0 n/a n/a n/a
2023-02-02 2022-12-31 13F SELLAS LIFE SCIENCES GROUP I PUT Put 1,200 -52.00 0 -100.00 n/a n/a n/a
2022-11-04 2022-09-30 13F SELLAS LIFE SCIENCES GROUP I PUT Put 2,500 -64.29 5 -66.67 n/a n/a n/a
2022-08-03 2022-06-30 13F SELLAS LIFE SCIENCES GROUP I PUT Put 7,000 -1.41 15 -68.09 n/a n/a n/a
2022-05-02 2022-03-31 13F SELLAS LIFE SCIENCES GROUP I PUT Put 7,100 1,320.00 47 2,250.00 n/a n/a n/a
2022-02-23 2021-12-31 13F/A SELLAS LIFE SCIENCES GROUP I PUT Put 500 -91.07 2 -96.15 n/a n/a n/a
2022-02-04 2021-12-31 13F SELLAS LIFE SCIENCES GROUP I PUT Put 5,600 52 n/a n/a n/a
2021-10-28 2021-09-30 13F SELLAS LIFE SCIENCES GROUP I PUT Put 5,600 0.00 52 -16.13 n/a n/a n/a
2021-08-12 2021-06-30 13F SELLAS LIFE SCIENCES GROUP I PUT Put 5,600 3,335.58 62 -55.40 n/a n/a n/a
2021-04-26 2021-03-31 13F SELLAS LIFE SCIENCES GROUP I PUT Put 163 139 n/a n/a n/a
2018-04-26 2018-03-31 13F GALENA BIOPHARMA PUT Put 0 -100.00 0 -100.00 n/a n/a n/a
2018-01-10 2017-12-31 13F GALENA BIOPHARMA PUT Put 3 0.00 0 n/a n/a n/a
2017-10-25 2017-09-30 13F GALENA BIOPHARMA PUT Put 3 -90.32 0 -100.00 n/a n/a n/a
2017-07-12 2017-06-30 13F GALENA BIOPHARMA PUT Put 31 -22.50 11 -35.29 n/a n/a n/a
2017-04-21 2017-03-31 13F GALENA BIOPHARMA PUT Put 40 -83.05 17 21.43 n/a n/a n/a
2017-01-11 2016-12-31 13F GALENA BIOPHARMA PUT Put 236 -50.21 14 -83.33 n/a n/a n/a
2016-10-07 2016-09-30 13F GALENA BIOPHARMA PUT Put 474 -16.55 84 18.31 n/a n/a n/a
2016-07-18 2016-06-30 13F GALENA BIOPHARMA PUT Put 568 153.57 71 108.82 n/a n/a n/a
2016-04-14 2016-03-31 13F GALENA BIOPHARMA PUT Put 224 96.49 34 41.67 n/a n/a n/a
2016-01-20 2015-12-31 13F GALENA BIOPHARMA PUT Put 114 235.29 24 41.18 n/a n/a n/a
2015-10-08 2015-09-30 13F GALENA BIOPHARMA PUT Put 34 142.86 17 183.33 n/a n/a n/a
2015-07-08 2015-06-30 13F GALENA BIOPHARMA PUT Put 14 -54.84 6 -40.00 n/a n/a n/a
2015-04-21 2015-03-31 13F GALENA BIOPHARMA PUT Put 31 -82.68 10 -54.55 n/a n/a n/a
2015-03-04 2014-12-31 13F GALENA BIOPHARMA PUT Put 179 22 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.