Arthur J. Gallagher & Co.
MX ˙ BMV ˙ US3635761097
SecurityMX:AJG / Arthur J. Gallagher & Co.
InstitutionNational Pension Service
Latest Disclosed Ownership498,276 shares
Latest Disclosed Value $ 107,916,616
National Pension Service reports 1.99% decrease in ownership of AJG / Arthur J. Gallagher & Co.

On May 12, 2026 - National Pension Service filed a 13F-HR form disclosing ownership of 498,276 shares of Arthur J. Gallagher & Co. (MX:AJG) valued at $107,916,616 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 10, 2026 disclosing 508,412 shares of Arthur J. Gallagher & Co.. This represents a change in shares of -1.99% 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)
2026-05-12 2026-03-31 13F GALLAGHER ARTHUR J COM 363576109 498,276 -10,136 -1.99 107,917 -17.98 0.0820
2026-02-10 2025-12-31 13F GALLAGHER ARTHUR J GALLAGHER ARTHUR J & CO 363576109 508,412 30,784 6.45 131,572 -11.06 0.0974
2025-11-04 2025-09-30 13F GALLAGHER ARTHUR J COM 363576109 477,628 7,281 1.55 147,940 -1.74 0.1149
2025-08-08 2025-06-30 13F GALLAGHER ARTHUR J COM 363576109 470,347 -33,756 -6.70 150,567 -13.49 0.1300
2025-05-13 2025-03-31 13F GALLAGHER ARTHUR J COM 363576109 504,103 58,382 13.10 174,037 37.56 0.1673
2025-02-05 2024-12-31 13F GALLAGHER ARTHUR J COM 363576109 445,721 -4,249 -0.94 126,518 -0.07 0.1197
2024-10-30 2024-09-30 13F GALLAGHERARTHURJ&CO COM 363576109 449,970 41,511 10.16 126,608 19.54 0.1221
2024-08-13 2024-06-30 13F GALLAGHER ARTHUR J COM 363576109 408,459 6,058 1.51 105,918 5.27 0.1217
2024-05-14 2024-03-31 13F GALLAGHER ARTHUR J COM 363576109 402,401 10,414 2.66 100,616 14.14 0.1207
2024-02-07 2023-12-31 13F GALLAGHER ARTHUR J COM 363576109 391,987 8,642 2.25 88,150 -0.42 0.1228
2023-11-15 2023-09-30 13F GALLAGHER ARTHUR J COM 363576109 383,345 4,077 1.07 88,526 8.73 0.1417
2023-08-16 2023-06-30 13F GALLAGHER ARTHUR J COM 363576109 379,268 24,345 6.86 81,417 20.94 0.1313
2023-05-12 2023-03-31 13F GALLAGHER ARTHUR J COM 363576109 354,923 23,348 7.04 67,318 7.68 0.1226
2023-02-24 2022-12-31 13F/A-1 GALLAGHER ARTHUR J COM 363576109 331,575 437 0.13 62,515 10.31 0.1230
2023-02-21 2022-12-31 13F GALLAGHER ARTHUR J COM 363576109 331,575 437 63 0.1230
2023-02-24 2022-09-30 13F/A-1 GALLAGHER ARTHUR J COM 363576109 331,138 203 0.06 56,671 5.03 0.1183
2022-11-18 2022-09-30 13F GALLAGHER ARTHUR J COM 363576109 331,138 203 56,671 0.1183
2022-08-17 2022-06-30 13F GALLAGHER ARTHUR J COM 363576109 330,935 21,584 6.98 53,956 -0.11 0.1112
2022-05-13 2022-03-31 13F GALLAGHER ARTHUR J COM 363576109 309,351 39,022 14.44 54,013 17.76 0.0986
2022-02-15 2021-12-31 13F GALLAGHER ARTHUR J COM 363576109 270,329 1,644 0.61 45,867 14.84 0.0800
2021-11-18 2021-09-30 13F GALLAGHER ARTHUR J COM 363576109 268,685 -19,324 -6.71 39,940 -1.00 0.0761
2021-08-17 2021-06-30 13F GALLAGHER ARTHUR J COM 363576109 288,009 2,000 0.70 40,344 13.06 0.0766
2021-05-14 2021-03-31 13F GALLAGHER ARTHUR J COM 363576109 286,009 5,088 1.81 35,685 2.68 0.0746
2021-02-19 2020-12-31 13F GALLAGHER ARTHUR J COM 363576109 280,921 2,206 0.79 34,753 18.80 0.0792
2020-11-13 2020-09-30 13F GALLAGHER ARTHUR J COM 363576109 278,715 0 0.00 29,254 7.66 0.0768
2020-08-11 2020-06-30 13F GALLAGHER ARTHUR J COM 363576109 278,715 -161 -0.06 27,172 19.54 0.0776
2020-05-27 2020-03-31 13F GALLAGHER ARTHUR J COM 363576109 278,876 0 0.00 22,731 -14.41 0.0769
2020-02-21 2019-12-31 13F GALLAGHER ARTHUR J COM 363576109 278,876 1,631 0.59 26,557 6.94 0.0729
2019-11-15 2019-09-30 13F GALLAGHER ARTHUR J COM 363576109 277,245 14,420 5.49 24,833 7.87 0.0786
2019-08-14 2019-06-30 13F GALLAGHER ARTHUR J COM 363576109 262,825 16,969 6.90 23,021 19.89 0.0769
2019-05-15 2019-03-31 13F GALLAGHER ARTHUR J COM 363576109 245,856 10,140 4.30 19,201 3.27 0.0739
2019-02-15 2018-12-31 13F GALLAGHER ARTHUR J COM 363576109 235,716 10,572 4.70 18,593 10.94 0.0767
2018-11-15 2018-09-30 13F GALLAGHER ARTHUR J COM 363576109 225,144 0 0.00 16,760 14.32 0.0682
2018-08-14 2018-06-30 13F GALLAGHER ARTHUR J COM 363576109 225,144 13,652 6.46 14,661 0.86 0.0663
2018-04-13 2018-03-31 13F GALLAGHER ARTHUR J COM 363576109 211,492 -1,266 -0.60 14,536 7.97 0.0721
2018-01-17 2017-12-31 13F GALLAGHER ARTHUR J COM 363576109 212,758 5,219 2.51 13,463 5.46 0.0672
2017-10-16 2017-09-30 13F GALLAGHER COM 363576109 207,539 7,970 3.99 12,766 12.19 0.0702
2017-07-13 2017-06-30 13F GALLAGHER ARTHUR J COM 363576109 199,569 17,422 9.56 11,379 10.05 0.0678
2017-04-11 2017-03-31 13F GALLAGHER ARTHUR J COM 363576109 182,147 181,832 57,724.44 10,340 64,525.00 0.0692
2017-01-18 2016-12-31 13F GALLAGHER ARTHUR J COM 363576109 315 315 16 0.0001
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.