Mercury Systems, Inc.
US ˙ NasdaqGS ˙ US5893781089

SecurityMRCY / Mercury Systems, Inc.
InstitutionState Street Corp
Latest Disclosed Ownership3,865,719 shares
Ownership 6.40%
State Street Corp ownership in MRCY / Mercury Systems, Inc.

2026-05-12 - State Street Corp has filed an SCHEDULE 13G form with the Securities and Exchange Commission (SEC) disclosing ownership of 3,865,719 shares of Mercury Systems, Inc. (US:MRCY). This represents 6.4 percent ownership of the company. In their previous filing dated 2025-05-13 , State Street Corp had reported owning 2,987,185 shares, indicating an increase of 29.41 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 2,987,185 3,865,719 29.41 6.40 28.00
2025-05-13 2025-05-13 13G 2,936,241 2,987,185 1.74 5.00 2.04
2025-02-05 2025-02-05 13G 3,536,048 2,936,241 -16.96 4.90 -17.92
2024-01-24 2024-01-24 13G 3,536,048 5.97

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 MERCURY SYS COM 589378108 3,865,719 442,119 12.91 281,850 12.76 0.0097
2026-02-13 2025-12-31 13F MERCURY SYS COM 589378108 3,423,600 368,242 12.05 249,957 5.70 0.0084
2025-11-14 2025-09-30 13F MERCURY SYS COM 589378108 3,055,358 -191,215 -5.89 236,485 35.24 0.0082
2025-08-14 2025-06-30 13F MERCURY SYS COM 589378108 3,246,573 259,388 8.68 174,860 35.85 0.0066
2025-05-15 2025-03-31 13F MERCURY SYS COM 589378108 2,987,185 50,944 1.74 128,718 4.37 0.0053
2025-02-14 2024-12-31 13F MERCURY SYS COM 589378108 2,936,241 -262,193 -8.20 123,322 4.21 0.0049
2024-11-14 2024-09-30 13F MERCURY SYS COM 589378108 3,198,434 -128,901 -3.87 118,342 31.78 0.0048
2024-08-14 2024-06-30 13F MERCURY SYS COM 589378108 3,327,335 -420,763 -11.23 89,805 -18.78 0.0039
2024-05-15 2024-03-31 13F MERCURY SYS COM 589378108 3,748,098 212,050 6.00 110,569 -14.50 0.0049
2024-02-14 2023-12-31 13F MERCURY SYS COM 589378108 3,536,048 487,051 15.97 129,313 14.35 0.0063
2023-11-14 2023-09-30 13F MERCURY SYS COM 589378108 3,048,997 468,013 18.13 113,087 26.67 0.0063
2023-08-14 2023-06-30 13F MERCURY SYS COM 589378108 2,580,984 -45,120 -1.72 89,276 -33.50 0.0047
2023-05-15 2023-03-31 13F MERCURY SYS COM 589378108 2,626,104 139,780 5.62 134,246 20.68 0.0076
2023-05-15 2022-12-31 13F/A-99 MERCURY SYS COM 589378108 2,486,324 -279,355 -10.10 111,238 -0.93 0.0065
2023-05-15 2022-12-31 13F MERCURY SYS COM 589378108 2,486,324 -279,355 111,238 0.0065
2022-11-15 2022-09-30 13F MERCURY SYS COM 589378108 2,765,679 382,507 16.05 112,287 -26.76 0.0071
2022-08-15 2022-06-30 13F MERCURY SYS COM 589378108 2,383,172 -70,162 -2.86 153,309 -3.04 0.0092
2022-05-16 2022-03-31 13F MERCURY SYS COM 589378108 2,453,334 76,459 3.22 158,117 20.82 0.0078
2022-02-14 2021-12-31 13F MERCURY SYS COM 589378108 2,376,875 85,631 3.74 130,871 20.45 0.0062
2021-11-15 2021-09-30 13F MERCURY SYS COM 589378108 2,291,244 48,623 2.17 108,651 -26.90 0.0057
2021-08-16 2021-06-30 13F MERCURY SYS COM 589378108 2,242,621 168,764 8.14 148,641 1.45 0.0078
2021-07-09 2021-03-31 13F/A-1 MERCURY SYS COM 589378108 2,073,857 160,367 8.38 146,518 -13.05 0.0084
2021-05-17 2021-03-31 13F MERCURY SYS COM 589378108 2,073,857 160,367 146,518 0.0084
2021-02-16 2020-12-31 13F MERCURY SYS COM 589378108 1,913,490 53,163 2.86 168,502 16.93 0.0103
2020-11-10 2020-09-30 13F MERCURY SYS COM 589378108 1,860,327 -178,435 -8.75 144,101 -10.14 0.0098
2020-08-14 2020-06-30 13F MERCURY SYS COM 589378108 2,038,762 -732,287 -26.43 160,369 -18.88 0.0117
2020-06-19 2020-03-31 13F/A-1 MERCURY SYS COM 589378108 2,771,049 16,719 0.61 197,687 3.85 0.0173
2020-05-11 2020-03-31 13F MERCURY SYS COM 589378108 2,771,049 16,719 197,687 17,360.8991
2020-02-06 2019-12-31 13F MERCURY SYS COM 589378108 2,754,330 285,248 11.55 190,352 -5.02 0.0130
2019-11-14 2019-09-30 13F MERCURY SYS COM 589378108 2,469,082 9,826 0.40 200,415 15.84 0.0149
2019-08-14 2019-06-30 13F MERCURY SYS COM 589378108 2,459,256 480,068 24.26 173,009 36.41 0.0129
2019-05-15 2019-03-31 13F MERCURY SYS COM 589378108 1,979,188 -149,996 -7.04 126,826 25.96 0.0099
2019-02-12 2018-12-31 13F MERCURY SYS COM 589378108 2,129,184 -245,812 -10.35 100,689 -23.36 0.0092
2018-11-09 2018-09-30 13F MERCURY SYSTEMS Common equity shares 589378108 2,374,996 8,086 0.34 131,386 45.84 0.0101
2018-08-14 2018-06-30 13F MERCURY SYSTEMS Common equity shares 589378108 2,366,910 376,984 18.94 90,090 -6.31 0.0075
2018-05-15 2018-03-31 13F MERCURY SYSTEMS Common equity shares 589378108 1,989,926 234,517 13.36 96,154 6.68 0.0082
2018-02-14 2017-12-31 13F MERCURY SYSTEMS Common equity shares 589378108 1,755,409 66,688 3.95 90,135 2.88 0.0072
2017-11-14 2017-09-30 13F MERCURY SYSTEMS Common equity shares 589378108 1,688,721 4,156 0.25 87,613 23.56 0.0076
2017-08-14 2017-06-30 13F MERCURY SYSTEMS Common equity shares 589378108 1,684,565 196,075 13.17 70,906 21.98 0.0063
2017-05-15 2017-03-31 13F MERCURY SYSTEMS Common equity shares 589378108 1,488,490 455,128 44.04 58,127 86.17 0.0052
2017-02-09 2016-12-31 13F MERCURY SYSTEMS Common equity shares 589378108 1,033,362 159,032 18.19 31,222 45.38 0.0029
2017-01-13 2016-09-30 13F/A-1 MERCURY SYSTEMS Common equity shares 589378108 874,330 45,558 5.50 21,476 4.23 0.0022
2016-11-14 2016-09-30 13F MERCURY SYSTEMS Common equity shares 589378108 874,330 21,476
2016-08-12 2016-06-30 13F MERCURY SYSTEMS Common equity shares 589378108 828,772 171,665 26.12 20,604 54.50 0.0022
2016-05-20 2016-03-31 13F/A-1 MERCURY SYSTEMS Common equity shares 589378108 657,107 30,270 4.83 13,336 15.91 0.0014
2016-05-12 2016-03-31 13F MERCURY SYSTEMS Common equity shares 589378108 657,107 13,336
2016-02-16 2015-12-31 13F MERCURY SYSTEMS Common equity shares 589378108 626,837 25,956 4.32 11,505 20.37 0.0013
2015-11-16 2015-09-30 13F MERCURY SYSTEMS Common equity shares 589378108 600,881 -4,451 -0.74 9,558 7.83 0.0011
2015-08-13 2015-06-30 13F MERCURY SYSTEMS Common equity shares 589378108 605,332 2,369 0.39 8,864 -5.42 0.0009
2015-05-15 2015-03-31 13F MERCURY SYSTEMS Common equity shares 589378108 602,963 32,532 5.70 9,372 17.98 0.0010
2015-02-11 2014-12-31 13F MERCURY SYSTEMS Common equity shares 589378108 570,431 -18,075 -3.07 7,944 22.57 0.0008
2014-11-12 2014-09-30 13F/A-1 MERCURY SYSTEMS Common equity shares 589378108 588,506 -14,519 -2.41 6,481 -5.22 0.0007
2014-11-10 2014-09-30 13F MERCURY SYSTEMS Common equity shares 589378108 588,506 6,481
2014-08-12 2014-06-30 13F MERCURY SYSTEMS Common equity shares 589378108 603,025 -5,702 -0.94 6,838 -14.98 0.0007
2014-05-15 2014-03-31 13F/A-1 MERCURY SYSTEMS Common equity shares 589378108 608,727 13,834 2.33 8,043 23.49 0.0009
2014-05-13 2014-03-31 13F MERCURY SYSTEMS Common equity shares 589378108 609,027 8,047
2014-02-06 2013-12-31 13F/A-1 MERCURY SYSTEMS Common equity shares 589378108 594,893 3,162 0.53 6,513 10.18 0.0007
2014-02-06 2013-12-31 13F MERCURY SYSTEMS Common equity shares 589378108 601,263 5,533
2013-11-12 2013-09-30 13F MERCURY SYSTEMS Common equity shares 589378108 591,731 20,018 3.50 5,911 12.10 0.0007
2013-08-08 2013-06-30 13F MERCURY SYSTEMS Common equity shares 589378108 571,713 571,713 5,273 0.0007
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.