Amylyx Pharmaceuticals, Inc.

SecurityAMLX / Amylyx Pharmaceuticals, Inc.
InstitutionCitadel Advisors Llc
ManagerKen Griffin
Latest Disclosed Ownership411,532 shares
Latest Disclosed Value $ 5,720,295
Citadel Advisors Llc ownership in AMLX / Amylyx Pharmaceuticals, Inc.

On May 15, 2026 - Citadel Advisors Llc filed a 13F-HR form disclosing ownership of 411,532 shares of Amylyx Pharmaceuticals, Inc. (US:AMLX) valued at $5,720,295 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 344,968 shares of Amylyx Pharmaceuticals, Inc.. This represents a change in shares of 19.30% during the quarter. The current value of the position is $5,481,606 USD.

Citadel Advisors Llc has a history of taking positions in derivatives of the underlying security (AMLX) in the form of stock options. The firm currently holds call options representing 45,300 of underlying shares valued at $629,670 USD and put options representing 12,800 of underlying shares valued at $177,920 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.

AMLX / Amylyx 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 AMYLYX PHARMACEUTICALS COM 03237H101 411,532 66,564 19.30 5,720 37.27 0.0008
2026-02-17 2025-12-31 13F AMYLYX PHARMACEUTICALS COM 03237H101 344,968 110,295 47.00 4,167 30.67 0.0006
2025-11-14 2025-09-30 13F AMYLYX PHARMACEUTICALS COM 03237H101 234,673 -1,008,254 -81.12 3,189 -59.97 0.0005
2025-08-14 2025-06-30 13F AMYLYX PHARMACEUTICALS COM 03237H101 1,242,927 -1,514,849 -54.93 7,967 -18.39 0.0014
2025-05-15 2025-03-31 13F AMYLYX PHARMACEUTICALS COM 03237H101 2,757,776 787,072 39.94 9,763 31.05 0.0019
2025-02-14 2024-12-31 13F AMYLYX PHARMACEUTICALS COM 03237H101 1,970,704 71,144 3.75 7,449 21.04 0.0013
2024-11-14 2024-09-30 13F AMYLYX PHARMACEUTICALS COM 03237H101 1,899,560 554,742 41.25 6,155 140.86 0.0012
2024-08-14 2024-06-30 13F AMYLYX PHARMACEUTICALS COM 03237H101 1,344,818 14,434 1.08 2,555 -32.37 0.0005
2024-05-15 2024-03-31 13F AMYLYX PHARMACEUTICALS COM 03237H101 1,330,384 -910,501 -40.63 3,778 -88.55 0.0007
2024-02-14 2023-12-31 13F AMYLYX PHARMACEUTICALS COM 03237H101 2,240,885 1,013,941 82.64 32,986 46.83 0.0066
2023-11-14 2023-09-30 13F AMYLYX PHARMACEUTICALS COM 03237H101 1,226,944 413,619 50.86 22,465 28.06 0.0048
2023-08-14 2023-06-30 13F AMYLYX PHARMACEUTICALS COM 03237H101 813,325 584,419 255.31 17,543 161.21 0.0036
2023-05-15 2023-03-31 13F AMYLYX PHARMACEUTICALS COM 03237H101 228,906 172,149 303.31 6,716 220.27 0.0015
2023-02-14 2022-12-31 13F AMYLYX PHARMACEUTICALS COM 03237H101 56,757 -750,073 -92.97 2,097 -90.77 0.0005
2022-11-14 2022-09-30 13F AMYLYX PHARMACEUTICALS COM 03237H101 806,830 52,420 6.95 22,712 56.32 0.0052
2022-08-15 2022-06-30 13F AMYLYX PHARMACEUTICALS COM 03237H101 754,410 252,774 50.39 14,529 125.40 0.0037
2022-05-16 2022-03-31 13F AMYLYX PHARMACEUTICALS COM 03237H101 501,636 501,636 6,446 0.0013
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 AMYLYX PHARMACEUTICALS COM Call 45,300 -59.52 630 -53.44 n/a n/a n/a
2026-02-17 2025-12-31 13F AMYLYX PHARMACEUTICALS COM Call 111,900 14.07 1,352 1.35 n/a n/a n/a
2025-11-14 2025-09-30 13F AMYLYX PHARMACEUTICALS COM Call 98,100 119.96 1,333 367.72 n/a n/a n/a
2025-08-14 2025-06-30 13F AMYLYX PHARMACEUTICALS COM Call 44,600 60.43 286 190.82 n/a n/a n/a
2025-05-15 2025-03-31 13F AMYLYX PHARMACEUTICALS COM Call 27,800 -79.41 98 -80.78 n/a n/a n/a
2025-02-14 2024-12-31 13F AMYLYX PHARMACEUTICALS COM Call 135,000 51.18 510 76.47 n/a n/a n/a
2024-11-14 2024-09-30 13F AMYLYX PHARMACEUTICALS COM Call 89,300 29.42 289 120.61 n/a n/a n/a
2024-08-14 2024-06-30 13F AMYLYX PHARMACEUTICALS COM Call 69,000 -84.80 131 -89.83 n/a n/a n/a
2024-05-15 2024-03-31 13F AMYLYX PHARMACEUTICALS COM Call 453,800 99.74 1,289 -61.48 n/a n/a n/a
2024-02-14 2023-12-31 13F AMYLYX PHARMACEUTICALS COM Call 227,200 98.78 3,344 59.85 n/a n/a n/a
2023-11-14 2023-09-30 13F AMYLYX PHARMACEUTICALS COM Call 114,300 111.28 2,093 79.42 n/a n/a n/a
2023-08-14 2023-06-30 13F AMYLYX PHARMACEUTICALS COM Call 54,100 -45.35 1,167 -59.85 n/a n/a n/a
2023-05-15 2023-03-31 13F AMYLYX PHARMACEUTICALS COM Call 99,000 91.49 2,905 52.04 n/a n/a n/a
2023-02-14 2022-12-31 13F AMYLYX PHARMACEUTICALS COM Call 51,700 -87.44 1,910 -83.52 n/a n/a n/a
2022-11-14 2022-09-30 13F AMYLYX PHARMACEUTICALS COM Call 411,700 64.48 11,589 140.39 n/a n/a n/a
2022-08-15 2022-06-30 13F AMYLYX PHARMACEUTICALS COM Call 250,300 4,821 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 AMYLYX PHARMACEUTICALS COM Put 12,800 178 n/a n/a n/a
2026-02-17 2025-12-31 13F AMYLYX PHARMACEUTICALS COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2025-11-14 2025-09-30 13F AMYLYX PHARMACEUTICALS COM Put 39,000 530 n/a n/a n/a
2025-08-14 2025-06-30 13F AMYLYX PHARMACEUTICALS COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2025-05-15 2025-03-31 13F AMYLYX PHARMACEUTICALS COM Put 35,300 -71.67 125 -73.62 n/a n/a n/a
2025-02-14 2024-12-31 13F AMYLYX PHARMACEUTICALS COM Put 124,600 -22.46 471 -9.62 n/a n/a n/a
2024-11-14 2024-09-30 13F AMYLYX PHARMACEUTICALS COM Put 160,700 15.03 521 96.23 n/a n/a n/a
2024-08-14 2024-06-30 13F AMYLYX PHARMACEUTICALS COM Put 139,700 -70.79 265 -80.49 n/a n/a n/a
2024-05-15 2024-03-31 13F AMYLYX PHARMACEUTICALS COM Put 478,200 257.67 1,358 -31.00 n/a n/a n/a
2024-02-14 2023-12-31 13F AMYLYX PHARMACEUTICALS COM Put 133,700 -6.57 1,968 -24.89 n/a n/a n/a
2023-11-14 2023-09-30 13F AMYLYX PHARMACEUTICALS COM Put 143,100 -13.90 2,620 -26.90 n/a n/a n/a
2023-08-14 2023-06-30 13F AMYLYX PHARMACEUTICALS COM Put 166,200 70.29 3,585 25.18 n/a n/a n/a
2023-05-15 2023-03-31 13F AMYLYX PHARMACEUTICALS COM Put 97,600 10.28 2,864 -12.45 n/a n/a n/a
2023-02-14 2022-12-31 13F AMYLYX PHARMACEUTICALS COM Put 88,500 -62.74 3,270 -51.09 n/a n/a n/a
2022-11-14 2022-09-30 13F AMYLYX PHARMACEUTICALS COM Put 237,500 201.01 6,686 339.87 n/a n/a n/a
2022-08-15 2022-06-30 13F AMYLYX PHARMACEUTICALS COM Put 78,900 1,520 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.