Xenon Pharmaceuticals Inc.
US ˙ NasdaqGM ˙ CA98420N1050

SecurityXENE / Xenon Pharmaceuticals Inc.
InstitutionCitadel Advisors Llc
ManagerKen Griffin
Latest Disclosed Ownership2,652,990 shares
Latest Disclosed Value $ 154,271,368
Citadel Advisors Llc ownership in XENE / Xenon Pharmaceuticals Inc.

On May 15, 2026 - Citadel Advisors Llc filed a 13F-HR form disclosing ownership of 2,652,990 shares of Xenon Pharmaceuticals Inc. (US:XENE) valued at $154,271,368 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 1,321,213 shares of Xenon Pharmaceuticals Inc.. This represents a change in shares of 100.80% during the quarter. The current value of the position is $137,239,173 USD.

Citadel Advisors Llc has a history of taking positions in derivatives of the underlying security (XENE) in the form of stock options. The firm currently holds call options representing 102,400 of underlying shares valued at $5,954,560 USD and put options representing 131,000 of underlying shares valued at $7,617,650 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.

XENE / Xenon Pharmaceuticals 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 XENON PHARMACEUTICALS COM 98420N105 2,652,990 1,331,777 100.80 154,271 160.52 0.0220
2026-02-17 2025-12-31 13F XENON PHARMACEUTICALS COM 98420N105 1,321,213 362,115 37.76 59,217 53.78 0.0089
2025-11-14 2025-09-30 13F XENON PHARMACEUTICALS COM 98420N105 959,098 839,053 698.95 38,508 924.94 0.0059
2025-08-14 2025-06-30 13F XENON PHARMACEUTICALS COM 98420N105 120,045 -567,043 -82.53 3,757 -83.70 0.0007
2025-05-15 2025-03-31 13F XENON PHARMACEUTICALS COM 98420N105 687,088 359,785 109.92 23,052 79.66 0.0044
2025-02-14 2024-12-31 13F XENON PHARMACEUTICALS COM 98420N105 327,303 -395,201 -54.70 12,830 -54.89 0.0022
2024-11-14 2024-09-30 13F XENON PHARMACEUTICALS COM 98420N105 722,504 -46,222 -6.01 28,445 -5.10 0.0055
2024-08-14 2024-06-30 13F XENON PHARMACEUTICALS COM 98420N105 768,726 -518,349 -40.27 29,973 -45.91 0.0061
2024-05-15 2024-03-31 13F XENON PHARMACEUTICALS COM 98420N105 1,287,075 20,231 1.60 55,409 -5.04 0.0107
2024-02-14 2023-12-31 13F XENON PHARMACEUTICALS COM 98420N105 1,266,844 543,320 75.09 58,351 136.09 0.0117
2023-11-14 2023-09-30 13F XENON PHARMACEUTICALS COM 98420N105 723,524 222,512 44.41 24,716 28.14 0.0053
2023-08-14 2023-06-30 13F XENON PHARMACEUTICALS COM 98420N105 501,012 -370,222 -42.49 19,289 -38.14 0.0040
2023-05-15 2023-03-31 13F XENON PHARMACEUTICALS COM 98420N105 871,234 -293,173 -25.18 31,181 -32.09 0.0069
2023-02-14 2022-12-31 13F XENON PHARMACEUTICALS COM 98420N105 1,164,407 22,405 1.96 45,913 11.37 0.0107
2022-11-14 2022-09-30 13F XENON PHARMACEUTICALS COM 98420N105 1,142,002 -506,037 -30.71 41,226 -17.77 0.0094
2022-08-15 2022-06-30 13F XENON PHARMACEUTICALS COM 98420N105 1,648,039 206,959 14.36 50,134 13.80 0.0129
2022-05-16 2022-03-31 13F XENON PHARMACEUTICALS COM 98420N105 1,441,080 153,277 11.90 44,053 9.50 0.0091
2022-02-14 2021-12-31 13F XENON PHARMACEUTICALS COM 98420N105 1,287,803 446,587 53.09 40,231 212.98 0.0082
2021-11-15 2021-09-30 13F XENON PHARMACEUTICALS Cmn 98420N105 841,216 -202,327 -19.39 12,854 -33.85 0.0027
2021-08-16 2021-06-30 13F XENON PHARMACEUTICALS COM 98420N105 1,043,543 820,991 368.90 19,431 387.73 0.0043
2021-05-21 2021-03-31 13F/A-1 XENON PHARMACEUTICALS COM 98420N105 222,552 151,002 211.04 3,984 261.85 0.0010
2021-05-17 2021-03-31 13F XENON PHARMACEUTICALS COM 98420N105 222,552 151,002 3,984 0.0010
2021-02-16 2020-12-31 13F XENON PHARMACEUTICALS COM 98420N105 71,550 -240,132 -77.04 1,101 -68.10 0.0003
2020-11-16 2020-09-30 13F XENON PHARMACEUTICALS COM 98420N105 311,682 -78,578 -20.13 3,451 -29.49 0.0010
2020-08-14 2020-06-30 13F XENON PHARMACEUTICALS Cmn 98420N105 390,260 -115,769 -22.88 4,894 -14.71 0.0017
2020-05-15 2020-03-31 13F XENON PHARMACEUTICALS Cmn 98420N105 506,029 273,764 117.87 5,738 88.44 0.0026
2020-02-14 2019-12-31 13F XENON PHARMACEUTICALS Cmn 98420N105 232,265 -39,820 -14.64 3,045 24.18 0.0013
2019-11-14 2019-09-30 13F XENON PHARMACEUTICALS Cmn 98420N105 272,085 -165,495 -37.82 2,452 -43.17 0.0012
2019-08-14 2019-06-30 13F XENON PHARMACEUTICALS Cmn 98420N105 437,580 -214,443 -32.89 4,315 -34.87 0.0020
2019-05-15 2019-03-31 13F XENON PHARMACEUTICALS Cmn 98420N105 652,023 -186,279 -22.22 6,625 25.26 0.0033
2019-02-14 2018-12-31 13F XENON PHARMACEUTICALS Cmn 98420N105 838,302 84,367 11.19 5,289 -46.85 0.0029
2018-11-13 2018-09-30 13F XENON PHARMACEUTICALS Cmn 98420N105 753,935 753,935 9,952 0.0045
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 XENON PHARMACEUTICALS COM Call 102,400 66.23 5,955 115.72 n/a n/a n/a
2026-02-17 2025-12-31 13F XENON PHARMACEUTICALS COM Call 61,600 176.23 2,761 208.38 n/a n/a n/a
2025-11-14 2025-09-30 13F XENON PHARMACEUTICALS COM Call 22,300 4.21 895 33.78 n/a n/a n/a
2025-08-14 2025-06-30 13F XENON PHARMACEUTICALS COM Call 21,400 177.92 670 159.30 n/a n/a n/a
2025-05-15 2025-03-31 13F XENON PHARMACEUTICALS COM Call 7,700 -47.62 258 -55.21 n/a n/a n/a
2025-02-14 2024-12-31 13F XENON PHARMACEUTICALS COM Call 14,700 -12.50 576 -12.86 n/a n/a n/a
2024-11-14 2024-09-30 13F XENON PHARMACEUTICALS COM Call 16,800 -47.17 661 -46.65 n/a n/a n/a
2024-08-14 2024-06-30 13F XENON PHARMACEUTICALS COM Call 31,800 181.42 1,240 154.94 n/a n/a n/a
2024-05-15 2024-03-31 13F XENON PHARMACEUTICALS COM Call 11,300 -33.14 486 -37.53 n/a n/a n/a
2024-02-14 2023-12-31 13F XENON PHARMACEUTICALS COM Call 16,900 -17.96 778 10.67 n/a n/a n/a
2023-11-14 2023-09-30 13F XENON PHARMACEUTICALS COM Call 20,600 50.36 704 33.40 n/a n/a n/a
2023-08-14 2023-06-30 13F XENON PHARMACEUTICALS COM Call 13,700 -64.51 527 -61.84 n/a n/a n/a
2023-05-15 2023-03-31 13F XENON PHARMACEUTICALS COM Call 38,600 28.67 1,381 16.84 n/a n/a n/a
2023-02-14 2022-12-31 13F XENON PHARMACEUTICALS COM Call 30,000 188.46 1,183 215.20 n/a n/a n/a
2022-11-14 2022-09-30 13F XENON PHARMACEUTICALS COM Call 10,400 -11.86 375 4.46 n/a n/a n/a
2022-08-15 2022-06-30 13F XENON PHARMACEUTICALS COM Call 11,800 359 n/a n/a n/a
2022-05-16 2022-03-31 13F XENON PHARMACEUTICALS COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2022-02-14 2021-12-31 13F XENON PHARMACEUTICALS COM Call 37,200 -86.23 1,162 -71.86 n/a n/a n/a
2021-11-15 2021-09-30 13F XENON PHARMACEUTICALS Cmn Call 270,200 4,129 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 XENON PHARMACEUTICALS COM Put 131,000 179.32 7,618 262.37 n/a n/a n/a
2026-02-17 2025-12-31 13F XENON PHARMACEUTICALS COM Put 46,900 60.07 2,102 78.74 n/a n/a n/a
2025-11-14 2025-09-30 13F XENON PHARMACEUTICALS COM Put 29,300 -19.95 1,176 2.71 n/a n/a n/a
2025-08-14 2025-06-30 13F XENON PHARMACEUTICALS COM Put 36,600 463.08 1,146 425.23 n/a n/a n/a
2025-05-15 2025-03-31 13F XENON PHARMACEUTICALS COM Put 6,500 209.52 218 165.85 n/a n/a n/a
2025-02-14 2024-12-31 13F XENON PHARMACEUTICALS COM Put 2,100 -41.67 82 -41.84 n/a n/a n/a
2024-11-14 2024-09-30 13F XENON PHARMACEUTICALS COM Put 3,600 -50.00 142 -49.64 n/a n/a n/a
2024-08-14 2024-06-30 13F XENON PHARMACEUTICALS COM Put 7,200 -31.43 281 -38.05 n/a n/a n/a
2024-05-15 2024-03-31 13F XENON PHARMACEUTICALS COM Put 10,500 -93.10 452 -93.55 n/a n/a n/a
2024-02-14 2023-12-31 13F XENON PHARMACEUTICALS COM Put 152,100 627.75 7,006 882.47 n/a n/a n/a
2023-11-14 2023-09-30 13F XENON PHARMACEUTICALS COM Put 20,900 397.62 714 342.86 n/a n/a n/a
2023-08-14 2023-06-30 13F XENON PHARMACEUTICALS COM Put 4,200 -44.00 162 -39.93 n/a n/a n/a
2023-05-15 2023-03-31 13F XENON PHARMACEUTICALS COM Put 7,500 -59.89 268 -63.64 n/a n/a n/a
2023-02-14 2022-12-31 13F XENON PHARMACEUTICALS COM Put 18,700 -25.50 737 -18.65 n/a n/a n/a
2022-11-14 2022-09-30 13F XENON PHARMACEUTICALS COM Put 25,100 80.58 906 114.18 n/a n/a n/a
2022-08-15 2022-06-30 13F XENON PHARMACEUTICALS COM Put 13,900 -23.20 423 -23.51 n/a n/a n/a
2022-05-16 2022-03-31 13F XENON PHARMACEUTICALS COM Put 18,100 66.06 553 62.17 n/a n/a n/a
2022-02-14 2021-12-31 13F XENON PHARMACEUTICALS COM Put 10,900 -85.56 341 -70.45 n/a n/a n/a
2021-11-15 2021-09-30 13F XENON PHARMACEUTICALS Cmn Put 75,500 209.43 1,154 154.19 n/a n/a n/a
2021-08-16 2021-06-30 13F XENON PHARMACEUTICALS COM Put 24,400 454 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.