Mercury Systems, Inc.
US ˙ NasdaqGS ˙ US5893781089

SecurityMRCY / Mercury Systems, Inc.
InstitutionSei Investments Co
Latest Disclosed Ownership378,357 shares
Latest Disclosed Value $ 27,623,990
Sei Investments Co ownership in MRCY / Mercury Systems, Inc.

On February 13, 2026 - Sei Investments Co filed a 13F-HR form disclosing ownership of 378,357 shares of Mercury Systems, Inc. (US:MRCY) valued at $27,623,845 USD as of December 31, 2025. The entity filed a previous 13F-HR on November 13, 2025 disclosing 311,561 shares of Mercury Systems, Inc.. This represents a change in shares of 21.44% during the quarter. The current value of the position is $42,220,858 USD.

Sei Investments Co has a history of taking positions in derivatives of the underlying security (MRCY) in the form of stock options.

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.

MRCY / Mercury Systems, 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)
2026-02-13 2025-12-31 13F MERCURY SYS COM 589378108 378,357 66,796 21.44 27,624 14.55 0.0273
2025-11-13 2025-09-30 13F MERCURY SYS COM 589378108 311,561 120,962 63.46 24,115 134.91 0.0259
2025-08-14 2025-06-30 13F MERCURY SYS COM 589378108 190,599 19,843 11.62 10,266 39.53 0.0119
2025-05-14 2025-03-31 13F/A-1 MERCURY SYS COM 589378108 170,756 26,570 18.43 7,358 21.50 0.0095
2025-05-13 2025-03-31 13F MERCURY SYS COM 589378108 159,750 15,564 6,732 0.0073
2025-02-11 2024-12-31 13F MERCURY SYS COM 589378108 144,186 13,103 10.00 6,056 24.85 0.0078
2024-11-12 2024-09-30 13F MERCURY SYS COM 589378108 131,083 -148,244 -53.07 4,850 -35.67 0.0063
2024-08-13 2024-06-30 13F MERCURY SYS COM 589378108 279,327 62,371 28.75 7,539 17.80 0.0107
2024-05-07 2024-03-31 13F MERCURY SYS COM 589378108 216,956 46,132 27.01 6,400 2.45 0.0094
2024-02-14 2023-12-31 13F MERCURY SYS COM 589378108 170,824 7,427 4.55 6,247 3.09 0.0100
2023-11-14 2023-09-30 13F MERCURY SYS COM 589378108 163,397 22,599 16.05 6,060 24.44 0.0109
2023-08-11 2023-06-30 13F MERCURY SYS COM 589378108 140,798 -24,647 -14.90 4,870 -42.41 0.0085
2023-05-12 2023-03-31 13F MERCURY SYS COM 589378108 165,445 33,318 25.22 8,457 43.07 0.0157
2023-02-10 2022-12-31 13F MERCURY SYS COM 589378108 132,127 -2,291 -1.70 5,911 8.32 0.0131
2022-11-14 2022-09-30 13F MERCURY SYS COM 589378108 134,418 -12,819 -8.71 5,457 -42.28 0.0122
2022-08-15 2022-06-30 13F MERCURY SYS COM 589378108 147,237 18,122 14.04 9,455 13.98 0.0204
2022-05-13 2022-03-31 13F MERCURY SYS COM 589378108 129,115 12,389 10.61 8,295 29.45 0.0167
2022-02-14 2021-12-31 13F MERCURY SYS COM 589378108 116,726 -1,464 -1.24 6,408 14.72 0.0120
2021-11-12 2021-09-30 13F MERCURY SYS COM 589378108 118,190 -4,732 -3.85 5,586 -31.36 0.0117
2021-08-06 2021-06-30 13F MERCURY SYS COM 589378108 122,922 23,850 24.07 8,138 15.30 0.0180
2021-05-12 2021-03-31 13F MERCURY SYS COM 589378108 99,072 2,886 3.00 7,058 -16.68 0.0178
2021-02-08 2020-12-31 13F MERCURY SYS COM 589378108 96,186 -28,299 -22.73 8,471 -12.14 0.0219
2020-12-04 2020-09-30 13F/A-1 MERCURY SYS COM 589378108 124,485 -19,241 -13.39 9,641 -14.76 0.0279
2020-11-06 2020-09-30 13F MERCURY SYS COM 589378108 125,013 -18,713 9,682 23,312.1033
2020-08-17 2020-06-30 13F/A-1 MERCURY SYS COM 589378108 143,726 17,538 13.90 11,310 25.49 0.0351
2020-08-11 2020-06-30 13F MERCURY SYS COM 589378108 123,241 -2,947 8,561 23,222.1682
2020-05-14 2020-03-31 13F MERCURY SYS COM 589378108 126,188 3,715 3.03 9,013 6.51 0.0331
2020-02-06 2019-12-31 13F MERCURY SYS COM 589378108 122,473 16,580 15.66 8,462 -1.57 0.0252
2019-11-12 2019-09-30 13F MERCURY SYS COM 589378108 105,893 10,970 11.56 8,597 28.72 0.0220
2019-08-14 2019-06-30 13F MERCURY SYS COM 589378108 94,923 -1,560 -1.62 6,679 7.99 0.0218
2019-05-15 2019-03-31 13F MERCURY SYS COM 589378108 96,483 -9,848 -9.26 6,185 5.65 0.0208
2019-02-13 2018-12-31 13F MERCURY SYS COM 589378108 106,331 937 0.89 5,854 0.34 0.0208
2018-11-08 2018-09-30 13F MERCURY SYS COM 589378108 105,394 10,169 10.68 5,834 60.98 0.0211
2018-08-03 2018-06-30 13F MERCURY SYS COM 589378108 95,225 7,819 8.95 3,624 -14.18 0.0123
2018-05-11 2018-03-31 13F MERCURY SYS COM 589378108 87,406 32,563 59.37 4,223 49.96 0.0162
2018-02-08 2017-12-31 13F MERCURY SYS COM 589378108 54,843 14,565 36.16 2,816 34.74 0.0098
2017-11-06 2017-09-30 13F MERCURY SYS COM 589378108 40,278 -357 -0.88 2,090 22.22 0.0074
2017-07-31 2017-06-30 13F MERCURY SYS COM 589378108 40,635 -2,417 -5.61 1,710 1.73 0.0068
2017-05-05 2017-03-31 13F MERCURY SYS COM 589378108 43,052 18,772 77.31 1,681 129.02 0.0074
2017-02-02 2016-12-31 13F MERCURY SYS COM 589378108 24,280 16,622 217.05 734 290.43 0.0036
2016-11-04 2016-09-30 13F MERCURY SYS COM 589378108 7,658 1,692 28.36 188 27.03 0.0010
2016-08-11 2016-06-30 13F MERCURY SYS COM 589378108 5,966 1,599 36.62 148 66.29 0.0009
2016-05-10 2016-03-31 13F/A-1 MERCURY SYS COM 589378108 4,367 -524 -10.71 89 -1.11 0.0006
2016-02-03 2015-12-31 13F MERCURY SYS COM 589378108 4,891 4,294 719.26 90 900.00 0.0005
2015-11-02 2015-09-30 13F/A-1 MERCURY SYS COM 589378108 597 0 0.00 9 0.00 0.0001
2015-10-30 2015-09-30 13F MERCURY SYS COM 589378108 597 11
2015-08-07 2015-06-30 13F/A-1 MERCK & CO INC PUT 589378108 0 -740 -100.00 0 -100.00
2015-08-07 2015-06-30 13F/A-1 MERCURY SYS COM 589378108 597 -143 -19.32 9 -18.18 0.0001
2015-08-04 2015-06-30 13F MERCURY SYS COM 589378108 597 -143 9 0.0001
2015-05-14 2015-03-31 13F/A-1 MERCURY SYS COM 589378108 740 433 141.04 11 175.00 0.0001
2015-05-01 2015-03-31 13F MERCK & CO INC PUT 589378108 740 740 11 0.0001
2015-02-10 2014-12-31 13F MERCURY SYS COM 589378108 307 307 4 0.0000
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
(%)
2015-08-07 2015-06-30 13F/A MERCK & CO INC PUT 0 -100.00 0 -100.00 n/a n/a n/a
2015-05-01 2015-03-31 13F MERCK & CO INC PUT 740 11 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.