Altimmune, Inc.
US ˙ NasdaqGM ˙ US02155H2004

SecurityALT / Altimmune, Inc.
InstitutionD. E. Shaw & Co., Inc.
ManagerDE Shaw
Latest Disclosed Ownership727,001 shares
Latest Disclosed Value $ 2,239,163
D. E. Shaw & Co., Inc. reports 45.89% decrease in ownership of ALT / Altimmune, Inc.

On May 15, 2026 - D. E. Shaw & Co., Inc. filed a 13F-HR form disclosing ownership of 727,001 shares of Altimmune, Inc. (US:ALT) valued at $2,239,163 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 1,343,583 shares of Altimmune, Inc.. This represents a change in shares of -45.89% during the quarter. The current value of the position is $2,086,493 USD.

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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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 ALTIMMUNE COM NEW 02155H200 727,001 -616,582 -45.89 2,239 -53.84 0.0010
2026-02-17 2025-12-31 13F ALTIMMUNE COM NEW 02155H200 1,343,583 983,188 272.81 4,850 257.14 0.0027
2025-11-14 2025-09-30 13F ALTIMMUNE COM NEW 02155H200 360,395 309,137 603.10 1,359 585.86 0.0008
2025-08-14 2025-06-30 13F ALTIMMUNE COM NEW 02155H200 51,258 742 1.47 198 -21.43 0.0001
2025-05-15 2025-03-31 13F ALTIMMUNE COM NEW 02155H200 50,516 -409,317 -89.01 253 -92.40 0.0002
2025-02-14 2024-12-31 13F ALTIMMUNE COM NEW 02155H200 459,833 -298,171 -39.34 3,315 -28.77 0.0024
2024-11-14 2024-09-30 13F ALTIMMUNE COM NEW 02155H200 758,004 -4,358 -0.57 4,654 -8.19 0.0040
2024-08-14 2024-06-30 13F ALTIMMUNE COM NEW 02155H200 762,362 408,012 115.14 5,070 40.53 0.0047
2024-05-15 2024-03-31 13F ALTIMMUNE COM NEW 02155H200 354,350 64,624 22.31 3,607 10.68 0.0031
2024-02-14 2023-12-31 13F ALTIMMUNE COM NEW 02155H200 289,726 -441,006 -60.35 3,259 71.62 0.0028
2023-11-14 2023-09-30 13F ALTIMMUNE COM NEW 02155H200 730,732 226,494 44.92 1,900 6.75 0.0020
2023-08-14 2023-06-30 13F ALTIMMUNE COM NEW 02155H200 504,238 504,238 1,780 0.0018
2023-05-15 2023-03-31 13F ALTIMMUNE COM NEW 02155H200 0 -27,702 -100.00 0 -100.00
2023-02-14 2022-12-31 13F ALTIMMUNE COM NEW 02155H200 27,702 27,702 456 0.0005
2022-11-14 2022-09-30 13F ALTIMMUNE COM NEW 02155H200 0 -169,683 -100.00 0 -100.00
2022-08-15 2022-06-30 13F ALTIMMUNE COM NEW 02155H200 169,683 -798,053 -82.47 1,985 -66.32 0.0023
2022-05-16 2022-03-31 13F ALTIMMUNE COM NEW 02155H200 967,736 -213,501 -18.07 5,893 -45.54 0.0055
2022-02-14 2021-12-31 13F ALTIMMUNE COM NEW 02155H200 1,181,237 225,799 23.63 10,820 0.13 0.0090
2021-11-15 2021-09-30 13F ALTIMMUNE COM NEW 02155H200 955,438 127,682 15.43 10,806 32.54 0.0098
2021-08-16 2021-06-30 13F ALTIMMUNE COM NEW 02155H200 827,756 -488,058 -37.09 8,153 -56.15 0.0070
2021-05-17 2021-03-31 13F ALTIMMUNE COM NEW 02155H200 1,315,814 122,120 10.23 18,593 38.08 0.0179
2021-02-16 2020-12-31 13F ALTIMMUNE COM NEW 02155H200 1,193,694 -467,136 -28.13 13,465 -38.58 0.0120
2020-11-16 2020-09-30 13F ALTIMMUNE COM NEW 02155H200 1,660,830 1,660,830 21,923 0.0224
2019-11-14 2019-09-30 13F ALTIMMUNE COM NEW 02155H200 0 -12,300 -100.00 0 -100.00
2019-08-14 2019-06-30 13F ALTIMMUNE COM NEW 02155H200 12,300 -800 -6.11 29 -23.68 0.0000
2019-05-15 2019-03-31 13F ALTIMMUNE COM NEW 02155H200 13,100 0 0.00 38 40.74 0.0000
2019-02-14 2018-12-31 13F ALTIMMUNE COM NEW 02155H200 13,100 13,100 27 0.0000
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.