Larimar Therapeutics, Inc.
US ˙ NasdaqGM ˙ US5171251003

SecurityLRMR / Larimar Therapeutics, Inc.
InstitutionCitadel Advisors Llc
ManagerKen Griffin
Latest Disclosed Ownership519,132 shares
Latest Disclosed Value $ 2,336,094
Citadel Advisors Llc ownership in LRMR / Larimar Therapeutics, Inc.

On May 15, 2026 - Citadel Advisors Llc filed a 13F-HR form disclosing ownership of 519,132 shares of Larimar Therapeutics, Inc. (US:LRMR) valued at $2,336,094 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 1,366,750 shares of Larimar Therapeutics, Inc.. This represents a change in shares of -62.02% during the quarter. The current value of the position is $1,645,648 USD.

Citadel Advisors Llc has a history of taking positions in derivatives of the underlying security (LRMR) in the form of stock options. The firm currently holds call options representing 32,200 of underlying shares valued at $144,900 USD and put options representing 48,800 of underlying shares valued at $219,600 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.

LRMR / Larimar Therapeutics, 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 LARIMAR THERAPEUTICS COM 517125100 519,132 -847,618 -62.02 2,336 -55.14 0.0003
2026-02-17 2025-12-31 13F LARIMAR THERAPEUTICS COM 517125100 1,366,750 -110,756 -7.50 5,207 9.12 0.0008
2025-11-14 2025-09-30 13F LARIMAR THERAPEUTICS COM 517125100 1,477,506 141,251 10.57 4,772 23.59 0.0007
2025-08-14 2025-06-30 13F LARIMAR THERAPEUTICS COM 517125100 1,336,255 901,969 207.69 3,862 313.83 0.0007
2025-05-15 2025-03-31 13F LARIMAR THERAPEUTICS COM 517125100 434,286 434,286 934 0.0002
2025-02-14 2024-12-31 13F LARIMAR THERAPEUTICS COM 517125100 0 -38,807 -100.00 0 -100.00
2024-11-14 2024-09-30 13F LARIMAR THERAPEUTICS COM 517125100 38,807 34,618 826.40 254 746.67 0.0000
2024-08-14 2024-06-30 13F LARIMAR THERAPEUTICS COM 517125100 4,189 -1,160,070 -99.64 30 -99.66 0.0000
2024-05-15 2024-03-31 13F LARIMAR THERAPEUTICS COM 517125100 1,164,259 481,900 70.62 8,837 184.66 0.0017
2024-02-14 2023-12-31 13F LARIMAR THERAPEUTICS COM 517125100 682,359 -296,827 -30.31 3,105 -19.73 0.0006
2023-11-14 2023-09-30 13F LARIMAR THERAPEUTICS COM 517125100 979,186 -197,469 -16.78 3,868 5.02 0.0008
2023-08-14 2023-06-30 13F LARIMAR THERAPEUTICS COM 517125100 1,176,655 500,217 73.95 3,683 20.17 0.0008
2023-05-15 2023-03-31 13F LARIMAR THERAPEUTICS COM 517125100 676,438 116,071 20.71 3,064 32.41 0.0007
2023-02-14 2022-12-31 13F LARIMAR THERAPEUTICS COM 517125100 560,367 544,766 3,491.87 2,314 4,528.00 0.0005
2022-11-14 2022-09-30 13F LARIMAR THERAPEUTICS COM 517125100 15,601 1,925 14.08 50 85.19 0.0000
2022-08-15 2022-06-30 13F LARIMAR THERAPEUTICS COM 517125100 13,676 779 6.04 27 -48.08 0.0000
2022-05-16 2022-03-31 13F LARIMAR THERAPEUTICS COM 517125100 12,897 12,897 52 0.0000
2022-02-14 2021-12-31 13F LARIMAR THERAPEUTICS Cmn 517125100 0 -309,260 -100.00 0 -100.00
2021-11-15 2021-09-30 13F LARIMAR THERAPEUTICS Cmn 517125100 309,260 1,117 0.36 3,566 17.85 0.0007
2021-08-16 2021-06-30 13F LARIMAR THERAPEUTICS COM 517125100 308,143 295,773 2,391.05 3,026 1,571.82 0.0007
2021-05-21 2021-03-31 13F/A-1 LARIMAR THERAPEUTICS COM 517125100 12,370 12,370 181 0.0000
2021-05-17 2021-03-31 13F LARIMAR THERAPEUTICS COM 517125100 12,370 12,370 181 0.0000
2020-08-14 2020-06-30 13F ZAFGEN Cmn 98885E103 0 -25,350 -100.00 0 -100.00
2020-05-15 2020-03-31 13F ZAFGEN Cmn 98885E103 25,350 -946,468 -97.39 20 -98.27 0.0000
2019-08-14 2019-06-30 13F ZAFGEN Cmn 98885E103 971,818 20,953 2.20 1,156 -55.62 0.0005
2019-05-15 2019-03-31 13F ZAFGEN Cmn 98885E103 950,865 -43,355 -4.36 2,605 -47.07 0.0013
2019-02-14 2018-12-31 13F ZAFGEN Cmn 98885E103 994,220 -51,332 -4.91 4,922 -59.73 0.0027
2018-11-13 2018-09-30 13F ZAFGEN Cmn 98885E103 1,045,552 545,914 109.26 12,223 139.10 0.0055
2018-08-14 2018-06-30 13F/A-1 ZAFGEN Cmn 98885E103 499,638 184,542 58.57 5,112 117.81 0.0025
2018-08-10 2018-06-30 13F ZAFGEN Cmn 98885E103 499,638 184,542 5,112
2018-05-14 2018-03-31 13F/A-1 ZAFGEN Cmn 98885E103 315,096 315,096 2,347 0.0013
2018-05-11 2018-03-31 13F ZAFGEN Cmn 98885E103 315,096 315,096 2,347
2016-08-12 2016-06-30 13F ZAFGEN Cmn 98885E103 0 -54,527 -100.00 0 -100.00
2017-01-31 2016-03-31 13F/A-1 ZAFGEN Cmn 98885E103 54,527 31,885 140.82 364 156.34 0.0005
2016-05-13 2016-03-31 13F ZAFGEN Cmn 98885E103 54,527 364
2017-01-31 2015-12-31 13F/A-1 ZAFGEN Cmn 98885E103 22,642 6,635 41.45 142 -72.21 0.0002
2016-02-12 2015-12-31 13F ZAFGEN Cmn 98885E103 22,642 142
2015-11-16 2015-09-30 13F ZAFGEN Cmn 98885E103 16,007 16,007 0.00 511 0.0005
2015-08-14 2015-06-30 13F ZAFGEN Cmn 98885E103 0 -39,472 -100.00 0 -100.00
2015-05-15 2015-03-31 13F ZAFGEN Cmn 98885E103 39,472 39,472 0.00 1,564 0.0017
2014-11-14 2014-09-30 13F ZAFGEN Cmn 98885E103 0 -15,816 -100.00 0 -100.00
2014-08-14 2014-06-30 13F ZAFGEN Cmn 98885E103 15,816 15,816 313 0.0004
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 LARIMAR THERAPEUTICS COM Call 32,200 145 n/a n/a n/a
2026-02-17 2025-12-31 13F LARIMAR THERAPEUTICS COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2025-11-14 2025-09-30 13F LARIMAR THERAPEUTICS COM Call 288,200 475.25 931 545.83 n/a n/a n/a
2025-08-14 2025-06-30 13F LARIMAR THERAPEUTICS COM Call 50,100 -2.91 145 30.91 n/a n/a n/a
2025-05-15 2025-03-31 13F LARIMAR THERAPEUTICS COM Call 51,600 89.71 111 4.76 n/a n/a n/a
2025-02-14 2024-12-31 13F LARIMAR THERAPEUTICS COM Call 27,200 12.86 105 -33.12 n/a n/a n/a
2024-11-14 2024-09-30 13F LARIMAR THERAPEUTICS COM Call 24,100 -33.97 158 -40.53 n/a n/a n/a
2024-08-14 2024-06-30 13F LARIMAR THERAPEUTICS COM Call 36,500 -66.42 265 -68.00 n/a n/a n/a
2024-05-15 2024-03-31 13F LARIMAR THERAPEUTICS COM Call 108,700 4,626.09 825 8,150.00 n/a n/a n/a
2024-02-14 2023-12-31 13F LARIMAR THERAPEUTICS COM Call 2,300 -47.73 10 -41.18 n/a n/a n/a
2023-11-14 2023-09-30 13F LARIMAR THERAPEUTICS COM Call 4,400 100.00 17 183.33 n/a n/a n/a
2023-08-14 2023-06-30 13F LARIMAR THERAPEUTICS COM Call 2,200 7 n/a n/a n/a
2023-05-15 2023-03-31 13F LARIMAR THERAPEUTICS COM Call 0 -100.00 0 n/a n/a n/a
2023-02-14 2022-12-31 13F LARIMAR THERAPEUTICS COM Call 100 0 n/a n/a n/a
2022-11-14 2022-09-30 13F LARIMAR THERAPEUTICS COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2022-08-15 2022-06-30 13F LARIMAR THERAPEUTICS COM Call 10,200 -42.70 20 -72.22 n/a n/a n/a
2022-05-16 2022-03-31 13F LARIMAR THERAPEUTICS COM Call 17,800 72 n/a n/a n/a
2016-05-13 2016-03-31 13F ZAFGEN Cmn Call 0 -100.00 0 -100.00 n/a n/a n/a
2017-01-31 2015-12-31 13F/A ZAFGEN Cmn Call 4,400 0.00 28 -80.14 n/a n/a n/a
2016-02-12 2015-12-31 13F ZAFGEN Cmn Call 4,400 28 n/a n/a n/a
2015-11-16 2015-09-30 13F ZAFGEN Cmn Call 4,400 141 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 LARIMAR THERAPEUTICS COM Put 48,800 178.86 220 231.82 n/a n/a n/a
2026-02-17 2025-12-31 13F LARIMAR THERAPEUTICS COM Put 17,500 -82.43 67 -79.44 n/a n/a n/a
2025-11-14 2025-09-30 13F LARIMAR THERAPEUTICS COM Put 99,600 66.00 322 85.55 n/a n/a n/a
2025-08-14 2025-06-30 13F LARIMAR THERAPEUTICS COM Put 60,000 294.74 173 440.63 n/a n/a n/a
2025-05-15 2025-03-31 13F LARIMAR THERAPEUTICS COM Put 15,200 -50.65 33 -73.11 n/a n/a n/a
2025-02-14 2024-12-31 13F LARIMAR THERAPEUTICS COM Put 30,800 4.76 119 -38.02 n/a n/a n/a
2024-11-14 2024-09-30 13F LARIMAR THERAPEUTICS COM Put 29,400 1,178.26 193 1,100.00 n/a n/a n/a
2024-08-14 2024-06-30 13F LARIMAR THERAPEUTICS COM Put 2,300 -87.36 17 -88.41 n/a n/a n/a
2024-05-15 2024-03-31 13F LARIMAR THERAPEUTICS COM Put 18,200 9,000.00 138 n/a n/a n/a
2024-02-14 2023-12-31 13F LARIMAR THERAPEUTICS COM Put 200 -71.43 1 -100.00 n/a n/a n/a
2023-11-14 2023-09-30 13F LARIMAR THERAPEUTICS COM Put 700 -50.00 3 -50.00 n/a n/a n/a
2023-08-14 2023-06-30 13F LARIMAR THERAPEUTICS COM Put 1,400 100.00 4 33.33 n/a n/a n/a
2023-05-15 2023-03-31 13F LARIMAR THERAPEUTICS COM Put 700 3 n/a n/a n/a
2016-11-10 2016-09-30 13F ZAFGEN Cmn Put 0 -100.00 0 -100.00 n/a n/a n/a
2017-01-31 2016-06-30 13F/A ZAFGEN Cmn Put 10,400 0.00 62 n/a n/a n/a
2016-08-12 2016-06-30 13F ZAFGEN Cmn Put 10,400 62 n/a n/a n/a
2017-01-31 2016-03-31 13F/A ZAFGEN Cmn Put 0 -100.00 0 -100.00 n/a n/a n/a
2017-01-31 2015-12-31 13F/A ZAFGEN Cmn Put 2,300 -28.12 14 -86.27 n/a n/a n/a
2016-02-12 2015-12-31 13F ZAFGEN Cmn Put 2,300 14 n/a n/a n/a
2015-11-16 2015-09-30 13F ZAFGEN Cmn Put 3,200 102 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.