Altimmune, Inc.
US ˙ NasdaqGM ˙ US02155H2004

SecurityALT / Altimmune, Inc.
InstitutionSimplex Trading, Llc
Latest Disclosed Ownership22,841 shares
Latest Disclosed Value $ 70,350
Simplex Trading, Llc ownership in ALT / Altimmune, Inc.

On May 14, 2026 - Simplex Trading, Llc filed a 13F-HR form disclosing ownership of 22,841 shares of Altimmune, Inc. (US:ALT) valued at $70,350 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 11, 2026 disclosing 0 shares of Altimmune, Inc.. The current value of the position is $65,554 USD.

Simplex Trading, Llc has a history of taking positions in derivatives of the underlying security (ALT) in the form of stock options. The firm currently holds call options representing 202,400 of underlying shares valued at $623,392 USD and put options representing 75,000 of underlying shares valued at $231,000 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.

ALT / Altimmune, 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 ALTIMMUNE COM 02155H200 22,841 22,841 70 0.0000
2026-02-11 2025-12-31 13F ALTIMMUNE COM 02155H200 0 -213,709 -100.00 0 0.0000
2025-11-12 2025-09-30 13F ALTIMMUNE COM 02155H200 213,709 113,742 113.78 1 0.0004
2025-08-05 2025-06-30 13F ALTIMMUNE COM 02155H200 99,967 79,146 380.13 0 0.0002
2025-05-12 2025-03-31 13F ALTIMMUNE COM 02155H200 20,821 -160,351 -88.51 0 -100.00 0.0001
2025-02-11 2024-12-31 13F ALTIMMUNE COM 02155H200 181,172 48,007 36.05 1 0.0007
2024-11-08 2024-09-30 13F ALTIMMUNE COM 02155H200 133,165 -32,924 -19.82 1 -100.00 0.0005
2024-07-25 2024-06-30 13F ALTIMMUNE COM 02155H200 166,089 19,830 13.56 1 0.00 0.0007
2024-04-25 2024-03-31 13F ALTIMMUNE COM 02155H200 146,259 81,128 124.56 1 0.0009
2024-02-02 2023-12-31 13F ALTIMMUNE COM 02155H200 65,131 -3,867 -5.60 1 0.0005
2023-11-01 2023-09-30 13F ALTIMMUNE COM 02155H200 68,998 20,662 42.75 0 0.0001
2023-08-04 2023-06-30 13F ALTIMMUNE COM 02155H200 48,336 48,336 0 0.0001
2023-04-27 2023-03-31 13F ALTIMMUNE COM 02155H200 0 -226,629 -100.00 0 -100.00
2023-02-02 2022-12-31 13F ALTIMMUNE COM 02155H200 226,629 88,886 64.53 4 -99.83 0.0041
2022-11-04 2022-09-30 13F ALTIMMUNE COM 02155H200 137,743 12,481 9.96 1,758 20.00 0.0020
2022-08-03 2022-06-30 13F ALTIMMUNE COM 02155H200 125,262 125,262 1,465 0.0016
2021-10-28 2021-09-30 13F ALTIMMUNE COM 02155H200 0 -6,985 -100.00 0 -100.00
2021-08-12 2021-06-30 13F ALTIMMUNE COM 02155H200 6,985 6,985 68 0.0001
2020-07-13 2020-06-30 13F ALTIMMUNE COM 02155H200 0 -94 -100.00 0 -100.00 0.0000
2020-04-29 2020-03-31 13F ALTIMMUNE COM 02155H200 94 94 0 0.0000
2017-07-12 2017-06-30 13F PHARMATHENE COM 71714G102 0 -1,079 -100.00 0 0.0000
2017-04-21 2017-03-31 13F PHARMATHENE COM 71714G102 1,079 -22,220 -95.37 0 -100.00
2017-01-11 2016-12-31 13F PHARMATHENE COM 71714G102 23,299 10,890 87.76 75 114.29 0.0045
2016-10-07 2016-09-30 13F PHARMATHENE COM 71714G102 12,409 12,409 35 0.0024
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 ALTIMMUNE CALL Call 202,400 -46.28 623 -54.19 n/a n/a n/a
2026-02-11 2025-12-31 13F ALTIMMUNE CALL Call 376,800 20.23 1,360 135,900.00 n/a n/a n/a
2025-11-12 2025-09-30 13F ALTIMMUNE CALL Call 313,400 -62.34 1 -66.67 n/a n/a n/a
2025-08-05 2025-06-30 13F ALTIMMUNE CALL Call 832,100 135.59 3 200.00 n/a n/a n/a
2025-05-12 2025-03-31 13F ALTIMMUNE CALL Call 353,200 -10.47 2 -50.00 n/a n/a n/a
2025-02-11 2024-12-31 13F ALTIMMUNE CALL Call 394,500 18.29 3 0.00 n/a n/a n/a
2024-11-08 2024-09-30 13F ALTIMMUNE CALL Call 333,500 52.56 2 100.00 n/a n/a n/a
2024-07-25 2024-06-30 13F ALTIMMUNE CALL Call 218,600 -4.08 1 -50.00 n/a n/a n/a
2024-04-25 2024-03-31 13F ALTIMMUNE CALL Call 227,900 -37.90 2 -50.00 n/a n/a n/a
2024-02-02 2023-12-31 13F ALTIMMUNE CALL Call 367,000 1,306.13 4 n/a n/a n/a
2023-11-01 2023-09-30 13F ALTIMMUNE CALL Call 26,100 87.77 0 n/a n/a n/a
2023-08-04 2023-06-30 13F ALTIMMUNE CALL Call 13,900 -90.36 0 n/a n/a n/a
2023-04-27 2023-03-31 13F ALTIMMUNE CALL Call 144,200 -46.53 1 -100.00 n/a n/a n/a
2023-02-02 2022-12-31 13F ALTIMMUNE CALL Call 269,700 46.50 4 -99.83 n/a n/a n/a
2022-11-04 2022-09-30 13F ALTIMMUNE CALL Call 184,100 2,201.25 2,350 2,426.88 n/a n/a n/a
2022-08-03 2022-06-30 13F ALTIMMUNE CALL Call 8,000 -60.00 93 -23.14 n/a n/a n/a
2022-05-02 2022-03-31 13F ALTIMMUNE CALL Call 20,000 124.72 121 49.38 n/a n/a n/a
2022-02-23 2021-12-31 13F/A ALTIMMUNE CALL Call 8,900 -73.75 81 -76.18 n/a n/a n/a
2022-02-04 2021-12-31 13F ALTIMMUNE CALL Call 33,900 340 n/a n/a n/a
2021-10-28 2021-09-30 13F ALTIMMUNE CALL Call 33,900 -2.02 340 0.00 n/a n/a n/a
2021-08-12 2021-06-30 13F ALTIMMUNE CALL Call 34,600 11,061.29 340 -22.37 n/a n/a n/a
2021-04-26 2021-03-31 13F ALTIMMUNE CALL Call 310 -30.96 438 28.82 n/a n/a n/a
2021-02-02 2020-12-31 13F ALTIMMUNE CALL Call 449 26.84 0 -100.00 n/a n/a n/a
2020-10-14 2020-09-30 13F ALTIMMUNE CALL Call 354 -3.54 0 -100.00 n/a n/a n/a
2020-07-13 2020-06-30 13F ALTIMMUNE CALL Call 367 -25.41 393 150.32 n/a n/a n/a
2020-04-29 2020-03-31 13F ALTIMMUNE CALL Call 492 6,050.00 157 15,600.00 n/a n/a n/a
2020-02-05 2019-12-31 13F ALTIMMUNE CALL Call 8 100.00 1 -99.36 n/a n/a n/a
2019-10-15 2019-09-30 13F ALTIMMUNE CALL Call 4 -85.19 0 -100.00 n/a n/a n/a
2019-07-26 2019-06-30 13F ALTIMMUNE CALL Call 27 -90.43 6 -92.59 n/a n/a n/a
2019-04-18 2019-03-31 13F ALTIMMUNE CALL Call 282 2,069.23 81 3,950.00 n/a n/a n/a
2019-01-16 2018-12-31 13F ALTIMMUNE CALL Call 13 -95.39 2 -97.53 n/a n/a n/a
2018-07-30 2018-06-30 13F ALTIMMUNE CALL Call 0 -100.00 0 n/a n/a n/a
2018-04-26 2018-03-31 13F ALTIMMUNE CALL Call 46 109.09 0 n/a n/a n/a
2018-01-10 2017-12-31 13F ALTIMMUNE CALL Call 22 -78.00 0 n/a n/a n/a
2017-10-25 2017-09-30 13F ALTIMMUNE CALL Call 100 400.00 0 n/a n/a n/a
2017-07-12 2017-06-30 13F ALTIMMUNE CALL Call 20 0.00 0 n/a n/a n/a
2017-04-21 2017-03-31 13F PHARMATHENE CALL Call 20 1,900.00 0 n/a n/a n/a
2017-01-11 2016-12-31 13F PHARMATHENE CALL Call 1 -96.00 0 n/a n/a n/a
2016-10-07 2016-09-30 13F PHARMATHENE CALL Call 25 -95.23 0 -100.00 n/a n/a n/a
2016-07-18 2016-06-30 13F PHARMATHENE CALL Call 524 351.72 10 400.00 n/a n/a n/a
2016-04-14 2016-03-31 13F PHARMATHENE CALL Call 116 582.35 2 -80.00 n/a n/a n/a
2016-01-20 2015-12-31 13F PHARMATHENE CALL Call 17 750.00 0 -100.00 n/a n/a n/a
2015-10-08 2015-09-30 13F PHARMATHENE CALL Call 2 -88.24 0 n/a n/a n/a
2015-07-08 2015-06-30 13F PHARMATHENE CALL Call 0 -100.00 0 n/a n/a n/a
2015-04-21 2015-03-31 13F PHARMATHENE CALL Call 20 0.00 0 n/a n/a n/a
2015-03-04 2014-12-31 13F PHARMATHENE CALL Call 20 0 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 ALTIMMUNE PUT Put 75,000 -86.67 231 -88.62 n/a n/a n/a
2026-02-11 2025-12-31 13F ALTIMMUNE PUT Put 562,600 13.86 2,031 202,900.00 n/a n/a n/a
2025-11-12 2025-09-30 13F ALTIMMUNE PUT Put 494,100 44.56 2 0.00 n/a n/a n/a
2025-08-05 2025-06-30 13F ALTIMMUNE PUT Put 341,800 204.63 1 n/a n/a n/a
2025-05-12 2025-03-31 13F ALTIMMUNE PUT Put 112,200 -60.16 1 -100.00 n/a n/a n/a
2025-02-11 2024-12-31 13F ALTIMMUNE PUT Put 281,600 41.15 2 100.00 n/a n/a n/a
2024-11-08 2024-09-30 13F ALTIMMUNE PUT Put 199,500 8.31 1 0.00 n/a n/a n/a
2024-07-25 2024-06-30 13F ALTIMMUNE PUT Put 184,200 26.34 1 0.00 n/a n/a n/a
2024-04-25 2024-03-31 13F ALTIMMUNE PUT Put 145,800 -16.97 1 0.00 n/a n/a n/a
2024-02-02 2023-12-31 13F ALTIMMUNE PUT Put 175,600 153.03 2 n/a n/a n/a
2023-11-01 2023-09-30 13F ALTIMMUNE PUT Put 69,400 79.79 0 n/a n/a n/a
2023-08-04 2023-06-30 13F ALTIMMUNE PUT Put 38,600 -81.38 0 n/a n/a n/a
2023-04-27 2023-03-31 13F ALTIMMUNE PUT Put 207,300 204.85 1 -100.00 n/a n/a n/a
2023-02-02 2022-12-31 13F ALTIMMUNE PUT Put 68,000 -71.04 1 -99.97 n/a n/a n/a
2022-11-04 2022-09-30 13F ALTIMMUNE PUT Put 234,800 1,889.83 2,998 2,072.46 n/a n/a n/a
2022-08-03 2022-06-30 13F ALTIMMUNE PUT Put 11,800 321.43 138 711.76 n/a n/a n/a
2022-05-02 2022-03-31 13F ALTIMMUNE PUT Put 2,800 100.00 17 41.67 n/a n/a n/a
2022-02-23 2021-12-31 13F/A ALTIMMUNE PUT Put 1,400 -92.09 12 -93.22 n/a n/a n/a
2022-02-04 2021-12-31 13F ALTIMMUNE PUT Put 17,700 177 n/a n/a n/a
2021-10-28 2021-09-30 13F ALTIMMUNE PUT Put 17,700 -11.06 177 -9.69 n/a n/a n/a
2021-08-12 2021-06-30 13F ALTIMMUNE PUT Put 19,900 13,914.08 196 -2.00 n/a n/a n/a
2021-04-26 2021-03-31 13F ALTIMMUNE PUT Put 142 21.37 200 2.04 n/a n/a n/a
2021-02-02 2020-12-31 13F ALTIMMUNE PUT Put 117 25.81 0 -100.00 n/a n/a n/a
2020-10-14 2020-09-30 13F ALTIMMUNE PUT Put 93 -35.42 0 -100.00 n/a n/a n/a
2020-07-13 2020-06-30 13F ALTIMMUNE PUT Put 144 -68.28 154 6.21 n/a n/a n/a
2020-04-29 2020-03-31 13F ALTIMMUNE PUT Put 454 45,300.00 145 -5.84 n/a n/a n/a
2020-02-05 2019-12-31 13F ALTIMMUNE PUT Put 1 -95.00 0 -100.00 n/a n/a n/a
2019-10-15 2019-09-30 13F ALTIMMUNE PUT Put 20 -78.02 3 -85.71 n/a n/a n/a
2019-07-26 2019-06-30 13F ALTIMMUNE PUT Put 91 26.39 21 5.00 n/a n/a n/a
2019-04-18 2019-03-31 13F ALTIMMUNE PUT Put 72 -20.88 20 -4.76 n/a n/a n/a
2018-10-23 2018-09-30 13F ALTIMMUNE PUT Put 0 -100.00 0 -100.00 n/a n/a n/a
2018-07-30 2018-06-30 13F ALTIMMUNE PUT Put 10 2 n/a n/a n/a
2017-07-12 2017-06-30 13F PHARMATHENE PUT Put 0 -100.00 0 -100.00 n/a n/a n/a
2017-04-21 2017-03-31 13F PHARMATHENE PUT Put 31 -94.66 0 -100.00 n/a n/a n/a
2017-01-11 2016-12-31 13F PHARMATHENE PUT Put 580 44.64 28 -67.82 n/a n/a n/a
2016-10-07 2016-09-30 13F PHARMATHENE PUT Put 401 2,984.62 87 210.71 n/a n/a n/a
2016-07-18 2016-06-30 13F PHARMATHENE PUT Put 13 0 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.