Altimmune, Inc.
US ˙ NasdaqGM ˙ US02155H2004

SecurityALT / Altimmune, Inc.
InstitutionState Street Corp
Latest Disclosed Ownership7,145,550 shares
Ownership 5.50%
State Street Corp ownership in ALT / Altimmune, Inc.

2026-05-12 - State Street Corp has filed an SCHEDULE 13G form with the Securities and Exchange Commission (SEC) disclosing ownership of 7,145,550 shares of Altimmune, Inc. (US:ALT). This represents 5.5 percent ownership of the company. In their previous filing dated 2024-10-17 , State Street Corp had reported owning 3,413,827 shares, indicating an increase of 109.31 percent.

Institutional Ownership: 13D/G Filings

This table shows a history of the 13D/G filings made by the investor and/or investor group. Note that the share values in this table are not directly comparable to any numbers shown in the 13F table (if any).

File
Date		Effective
Date		Form Prev
Shares		 Latest
Shares		 ΔShares
(Percent)		 Ownership
(Percent)		 ΔOwnership
(Percent)
2026-05-12 2026-05-12 13G 3,413,827 7,145,550 109.31 5.50 14.58
2024-10-17 2024-10-17 13G/A 3,909,286 3,413,827 -12.67 4.80 -12.89
2024-07-10 2024-07-10 13G/A 8,649,270 3,909,286 -54.80 5.51 -54.84
2024-04-10 2024-04-10 13G/A 1,014,546 8,649,270 752.53 12.20 545.50
2024-01-23 2024-01-23 13G/A 804,073 1,014,546 26.18 1.89 15.95
2023-07-10 2023-07-10 13G/A 5,914,588 804,073 -86.41 1.63 -86.45
2023-01-10 2023-01-10 13G/A 691,141 5,914,588 755.77 12.03 651.88
2022-04-11 2022-04-11 13G/A 4,421,541 691,141 -84.37 1.60 -85.62
2022-02-11 2022-02-11 13G/A 3,991,141 4,421,541 10.78 11.13 10.75
2021-09-10 2021-09-10 13G 3,991,141 10.05

Important Note: One of the primary uses of the 13D/G filings is to evaluate the ability of a firm to control a company (ie, the "beneficial ownership"). To that end, firms are required to report not just direct holdings in companies, but indirect holdings that they control. For investment firms, these indirect holdings can include shares in funds they manage, advisory accounts, and in the case of activist campaigns, pledged votes. Therefore, share counts listed in 13D/G filings can differ significantly than share counts listed in 13F filings.

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 7,145,550 2,025,847 39.57 22,008 19.08 0.0008
2026-02-13 2025-12-31 13F ALTIMMUNE COM NEW 02155H200 5,119,703 1,518,448 42.16 18,482 36.14 0.0006
2025-11-14 2025-09-30 13F ALTIMMUNE COM NEW 02155H200 3,601,255 847,617 30.78 13,577 27.40 0.0005
2025-08-14 2025-06-30 13F ALTIMMUNE COM NEW 02155H200 2,753,638 -637,933 -18.81 10,657 -37.16 0.0004
2025-05-15 2025-03-31 13F ALTIMMUNE COM NEW 02155H200 3,391,571 -78,446 -2.26 16,958 -32.22 0.0007
2025-02-14 2024-12-31 13F ALTIMMUNE COM NEW 02155H200 3,470,017 56,190 1.65 25,019 19.36 0.0010
2024-11-14 2024-09-30 13F ALTIMMUNE COM NEW 02155H200 3,413,827 -495,459 -12.67 20,961 -19.37 0.0009
2024-08-14 2024-06-30 13F ALTIMMUNE COM NEW 02155H200 3,909,286 -4,739,984 -54.80 25,997 -70.48 0.0011
2024-05-15 2024-03-31 13F ALTIMMUNE COM NEW 02155H200 8,649,270 7,634,724 752.53 88,050 671.48 0.0039
2024-02-14 2023-12-31 13F ALTIMMUNE COM NEW 02155H200 1,014,546 143,665 16.50 11,414 404.11 0.0006
2023-11-14 2023-09-30 13F ALTIMMUNE COM NEW 02155H200 870,881 66,808 8.31 2,264 -20.23 0.0001
2023-08-14 2023-06-30 13F ALTIMMUNE COM NEW 02155H200 804,073 -4,155,181 -83.79 2,838 -86.44 0.0001
2023-05-15 2023-03-31 13F ALTIMMUNE COM NEW 02155H200 4,959,254 -955,334 -16.15 20,928 -78.49 0.0012
2023-05-15 2022-12-31 13F/A-99 ALTIMMUNE COM NEW 02155H200 5,914,588 2,515,732 74.02 97,295 124.16 0.0057
2023-05-15 2022-12-31 13F ALTIMMUNE COM NEW 02155H200 5,914,588 2,515,732 97,295 0.0057
2022-11-15 2022-09-30 13F ALTIMMUNE COM NEW 02155H200 3,398,856 3,263,310 2,407.53 43,403 2,636.63 0.0027
2022-08-15 2022-06-30 13F ALTIMMUNE COM NEW 02155H200 135,546 -555,595 -80.39 1,586 -62.32 0.0001
2022-05-16 2022-03-31 13F ALTIMMUNE COM NEW 02155H200 691,141 -3,730,400 -84.37 4,209 -89.61 0.0002
2022-02-14 2021-12-31 13F ALTIMMUNE COM NEW 02155H200 4,421,541 897,523 25.47 40,501 1.62 0.0019
2021-11-15 2021-09-30 13F ALTIMMUNE COM NEW 02155H200 3,524,018 -159,298 -4.32 39,857 9.86 0.0021
2021-08-16 2021-06-30 13F ALTIMMUNE COM NEW 02155H200 3,683,316 741,137 25.19 36,281 -12.73 0.0019
2021-07-09 2021-03-31 13F/A-1 ALTIMMUNE COM NEW 02155H200 2,942,179 2,942,179 41,573 0.0024
2021-05-17 2021-03-31 13F ALTIMMUNE COM NEW 02155H200 2,942,179 2,942,179 41,573 0.0024
2017-08-14 2017-06-30 13F PHARMATHENE Common equity shares 71714G102 0 -909,132 -100.00 0 -100.00
2017-05-15 2017-03-31 13F PHARMATHENE Common equity shares 71714G102 909,132 -17,724 -1.91 738 -75.51 0.0001
2017-02-09 2016-12-31 13F PHARMATHENE Common equity shares 71714G102 926,856 163,198 21.37 3,013 35.90 0.0003
2017-01-13 2016-09-30 13F/A-1 PHARMATHENE Common equity shares 71714G102 763,658 179,181 30.66 2,217 55.36 0.0002
2016-11-14 2016-09-30 13F PHARMATHENE Common equity shares 71714G102 763,658 2,217
2016-08-12 2016-06-30 13F PHARMATHENE Common equity shares 71714G102 584,477 567,777 3,399.86 1,427 4,359.38 0.0002
2016-05-20 2016-03-31 13F/A-1 PHARMATHENE Common equity shares 71714G102 16,700 0 0.00 32 0.00 0.0000
2016-05-12 2016-03-31 13F PHARMATHENE Common equity shares 71714G102 16,700 32
2016-02-16 2015-12-31 13F PHARMATHENE Common equity shares 71714G102 16,700 0 0.00 32 45.45 0.0000
2015-11-16 2015-09-30 13F PHARMATHENE Common equity shares 71714G102 16,700 0 0.00 22 -29.03 0.0000
2015-08-13 2015-06-30 13F PHARMATHENE Common equity shares 71714G102 16,700 0 0.00 31 19.23 0.0000
2015-05-15 2015-03-31 13F PHARMATHENE Common equity shares 71714G102 16,700 0 0.00 26 -16.13 0.0000
2015-02-11 2014-12-31 13F PHARMATHENE Common equity shares 71714G102 16,700 -1,900 -10.22 31 -8.82 0.0000
2014-11-12 2014-09-30 13F/A-1 PHARMATHENE Common equity shares 71714G102 18,600 0 0.00 34 30.77 0.0000
2014-11-10 2014-09-30 13F PHARMATHENE Common equity shares 71714G102 18,600 34
2014-08-12 2014-06-30 13F PHARMATHENE Common equity shares 71714G102 18,600 0 0.00 26 -23.53 0.0000
2014-05-15 2014-03-31 13F/A-1 PHARMATHENE Common equity shares 71714G102 18,600 0 0.00 34 -2.86 0.0000
2014-05-13 2014-03-31 13F PHARMATHENE Common equity shares 71714G102 18,600 34
2014-02-06 2013-12-31 13F/A-1 PHARMATHENE Common equity shares 71714G102 18,600 0 0.00 35 -10.26 0.0000
2014-02-06 2013-12-31 13F PHARMATHENE Common equity shares 71714G102 18,600 21
2013-11-12 2013-09-30 13F PHARMATHENE Common equity shares 71714G102 18,600 0 0.00 39 34.48 0.0000
2013-08-08 2013-06-30 13F PHARMATHENE Common equity shares 71714G102 18,600 18,600 29 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.