Arthur J. Gallagher & Co.
MX ˙ BMV ˙ US3635761097
SecurityMX:AJG / Arthur J. Gallagher & Co.
InstitutionSei Investments Co
Latest Disclosed Ownership212,544 shares
Latest Disclosed Value $ 55,005,127
Sei Investments Co reports 3.76% increase in ownership of AJG / Arthur J. Gallagher & Co.

On February 13, 2026 - Sei Investments Co filed a 13F-HR form disclosing ownership of 212,544 shares of Arthur J. Gallagher & Co. (MX:AJG) valued at $55,005,127 USD as of December 31, 2025. The entity filed a previous 13F-HR on November 13, 2025 disclosing 204,836 shares of Arthur J. Gallagher & Co.. This represents a change in shares of 3.76% during the quarter.

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)
2026-02-13 2025-12-31 13F GALLAGHER ARTHUR J COM 363576109 212,544 7,708 3.76 55,005 -13.31 0.0543
2025-11-13 2025-09-30 13F GALLAGHER ARTHUR J COM 363576109 204,836 -179,986 -46.77 63,450 -48.49 0.0682
2025-08-14 2025-06-30 13F GALLAGHER ARTHUR J COM 363576109 384,822 -2,512 -0.65 123,186 -7.88 0.1428
2025-05-14 2025-03-31 13F/A-1 GALLAGHER ARTHUR J COM 363576109 387,334 -355,412 -47.85 133,725 -36.57 0.1721
2025-05-13 2025-03-31 13F GALLAGHER ARTHUR J COM 363576109 744,457 1,711 213,424 0.2321
2025-02-11 2024-12-31 13F GALLAGHER ARTHUR J COM 363576109 742,746 560,325 307.16 210,829 310.75 0.2708
2024-11-12 2024-09-30 13F GALLAGHER ARTHUR J COM 363576109 182,421 -18,150 -9.05 51,328 -1.32 0.0667
2024-08-13 2024-06-30 13F GALLAGHER ARTHUR J COM 363576109 200,571 6,003 3.09 52,012 6.91 0.0737
2024-05-07 2024-03-31 13F GALLAGHER ARTHUR J COM 363576109 194,568 20,302 11.65 48,649 24.15 0.0713
2024-02-14 2023-12-31 13F GALLAGHER ARTHUR J COM 363576109 174,266 46,628 36.53 39,185 34.69 0.0629
2023-11-14 2023-09-30 13F GALLAGHER ARTHUR J COM 363576109 127,638 -1,859 -1.44 29,093 2.31 0.0523
2023-08-11 2023-06-30 13F GALLAGHER ARTHUR J COM 363576109 129,497 26,416 25.63 28,436 44.21 0.0496
2023-05-12 2023-03-31 13F GALLAGHER ARTHUR J COM 363576109 103,081 24,149 30.59 19,720 32.50 0.0366
2023-02-10 2022-12-31 13F GALLAGHER ARTHUR J COM 363576109 78,932 -1,797 -2.23 14,883 7.66 0.0331
2022-11-14 2022-09-30 13F GALLAGHER ARTHUR J COM 363576109 80,729 4,922 6.49 13,823 11.85 0.0308
2022-08-15 2022-06-30 13F GALLAGHER ARTHUR J COM 363576109 75,807 -6,254 -7.62 12,359 -13.74 0.0267
2022-05-13 2022-03-31 13F GALLAGHER ARTHUR J COM 363576109 82,061 -15,140 -15.58 14,327 -13.16 0.0288
2022-02-14 2021-12-31 13F GALLAGHER ARTHUR J COM 363576109 97,201 -2,916 -2.91 16,499 10.87 0.0310
2021-11-12 2021-09-30 13F GALLAGHER ARTHUR J COM 363576109 100,117 -8,216 -7.58 14,882 -1.93 0.0312
2021-08-06 2021-06-30 13F GALLAGHER ARTHUR J COM 363576109 108,333 -6,181 -5.40 15,175 6.21 0.0336
2021-05-12 2021-03-31 13F GALLAGHER ARTHUR J COM 363576109 114,514 -4,901 -4.10 14,288 -3.28 0.0360
2021-02-08 2020-12-31 13F GALLAGHER ARTHUR J COM 363576109 119,415 -19,548 -14.07 14,773 0.69 0.0382
2020-12-04 2020-09-30 13F/A-1 GALLAGHER ARTHUR J COM 363576109 138,963 13,526 10.78 14,672 19.98 0.0425
2020-11-06 2020-09-30 13F GALLAGHER ARTHUR J COM 363576109 139,060 13,623 14,682 35,350.9916
2020-08-17 2020-06-30 13F/A-1 GALLAGHER ARTHUR J COM 363576109 125,437 22,583 21.96 12,229 45.86 0.0380
2020-08-11 2020-06-30 13F GALLAGHER ARTHUR J COM 363576109 115,459 12,605 10,995 29,824.5228
2020-05-14 2020-03-31 13F GALLAGHER ARTHUR J COM 363576109 102,854 -12,564 -10.89 8,384 -23.72 0.0308
2020-02-06 2019-12-31 13F GALLAGHER ARTHUR J COM 363576109 115,418 -38,256 -24.89 10,991 -20.15 0.0328
2019-11-12 2019-09-30 13F GALLAGHER ARTHUR J COM 363576109 153,674 -31,487 -17.01 13,765 -15.13 0.0352
2019-08-14 2019-06-30 13F GALLAGHER ARTHUR J COM 363576109 185,161 -713 -0.38 16,219 11.73 0.0530
2019-05-15 2019-03-31 13F GALLAGHER ARTHUR J COM 363576109 185,874 -24,083 -11.47 14,516 -7.12 0.0487
2019-02-13 2018-12-31 13F GALLAGHER ARTHUR J COM 363576109 209,957 -18,276 -8.01 15,629 -8.01 0.0556
2018-11-08 2018-09-30 13F GALLAGHER ARTHUR J COM 363576109 228,233 21,932 10.63 16,990 26.16 0.0616
2018-08-03 2018-06-30 13F GALLAGHER ARTHUR J COM 363576109 206,301 24,694 13.60 13,467 7.89 0.0458
2018-05-11 2018-03-31 13F GALLAGHER ARTHUR J COM 363576109 181,607 -30,668 -14.45 12,482 -7.08 0.0478
2018-02-08 2017-12-31 13F GALLAGHER ARTHUR J COM 363576109 212,275 -11,202 -5.01 13,433 -2.33 0.0466
2017-11-06 2017-09-30 13F GALLAGHER ARTHUR J COM 363576109 223,477 8,211 3.81 13,754 11.60 0.0489
2017-07-31 2017-06-30 13F GALLAGHER ARTHUR J COM 363576109 215,266 42,310 24.46 12,324 26.03 0.0491
2017-05-05 2017-03-31 13F GALLAGHER ARTHUR J COM 363576109 172,956 -30,613 -15.04 9,779 -7.54 0.0429
2017-02-02 2016-12-31 13F GALLAGHER ARTHUR J COM 363576109 203,569 -34,306 -14.42 10,577 -12.59 0.0512
2016-11-04 2016-09-30 13F GALLAGHER ARTHUR J COM 363576109 237,875 -2,532 -1.05 12,101 5.75 0.0615
2016-08-11 2016-06-30 13F GALLAGHER ARTHUR J COM 363576109 240,407 187,767 356.70 11,443 388.81 0.0686
2016-05-10 2016-03-31 13F/A-1 GALLAGHER ARTHUR J COM 363576109 52,640 21,549 69.31 2,341 83.90 0.0146
2016-02-03 2015-12-31 13F GALLAGHER ARTHUR J COM 363576109 31,091 -16,004 -33.98 1,273 -34.52 0.0078
2015-11-02 2015-09-30 13F/A-1 GALLAGHER ARTHUR J COM 363576109 47,095 -10,114 -17.68 1,944 -28.16 0.0178
2015-10-30 2015-09-30 13F GALLAGHER ARTHUR J COM 363576109 47,095 1,946
2015-08-07 2015-06-30 13F/A-1 GALLAGHER ARTHUR J COM 363576109 57,209 -31,514 -35.52 2,706 -34.73 0.0245
2015-08-04 2015-06-30 13F GALLAGHER ARTHUR J COM 363576109 57,209 -31,514 2,706 0.0245
2015-05-14 2015-03-31 13F/A-1 GALLAGHER ARTHUR J COM 363576109 88,723 16,367 22.62 4,146 21.80 0.0360
2015-05-01 2015-03-31 13F GAIN CAP HLDGS NOTE 4.125%12/0 363576109 88,723 4,146
2015-02-10 2014-12-31 13F GALLAGHER ARTHUR J COM 363576109 72,356 72,356 3,404 0.0301
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.