Arthur J. Gallagher & Co.
MX ˙ BMV ˙ US3635761097
SecurityMX:AJG / Arthur J. Gallagher & Co.
InstitutionRathbone Brothers plc
Latest Disclosed Ownership35,114 shares
Latest Disclosed Value $ 7,604,990
Rathbone Brothers plc reports 2.23% increase in ownership of AJG / Arthur J. Gallagher & Co.

On May 12, 2026 - Rathbone Brothers plc filed a 13F-HR form disclosing ownership of 35,114 shares of Arthur J. Gallagher & Co. (MX:AJG) valued at $7,604,990 USD as of March 31, 2026. The entity filed a previous 13F-HR/A on February 6, 2026 disclosing 34,349 shares of Arthur J. Gallagher & Co.. This represents a change in shares of 2.23% 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 AJ & CO USD1 COM 363576109 35,114 765 2.23 7,605 -14.46 0.0325
2026-02-06 2025-12-31 13F/A-1 GALLAGHER AJ & CO USD1 COM 363576109 34,349 -50 -0.15 8,889 -16.57 0.0352
2026-01-21 2025-12-31 13F GALLAGHER AJ & CO USD1 COM 363576109 34,349 -50 8,889 0.0352
2025-11-13 2025-09-30 13F GALLAGHER AJ & CO USD1 COM 363576109 34,399 795 2.37 10,655 -0.96 0.0433
2025-08-07 2025-06-30 13F GALLAGHER AJ & CO USD1 COM 363576109 33,604 2,642 8.53 10,757 0.64 0.0464
2025-05-13 2025-03-31 13F GALLAGHER AJ & CO USD1 COM 363576109 30,962 0 0.00 10,689 21.63 0.0517
2025-02-13 2024-12-31 13F GALLAGHER AJ & CO USD1 COM 363576109 30,962 647 2.13 8,789 3.04 0.0425
2024-11-13 2024-09-30 13F GALLAGHER AJ & CO USD1 COM 363576109 30,315 -500 -1.62 8,530 6.75 0.0430
2024-08-09 2024-06-30 13F GALLAGHER AJ & CO USD1 COM 363576109 30,815 -86,090 -73.64 7,991 -72.67 0.0435
2024-05-14 2024-03-31 13F GALLAGHER AJ & CO USD1 COM 363576109 116,905 90 0.08 29,231 11.27 0.1687
2024-02-13 2023-12-31 13F GALLAGHER AJ & CO USD1 COM 363576109 116,815 -1,010 -0.86 26,269 -2.18 0.1693
2023-11-13 2023-09-30 13F GALLAGHER AJ & CO USD1 COM 363576109 117,825 30 0.03 26,856 3.83 0.1948
2023-08-04 2023-06-30 13F GALLAGHER AJ & CO USD1 COM 363576109 117,795 -80 -0.07 25,864 14.70 0.2414
2023-05-12 2023-03-31 13F GALLAGHER AJ & CO USD1 COM 363576109 117,875 -150 -0.13 22,551 1.34 0.2306
2023-02-14 2022-12-31 13F GALLAGHER AJ & CO USD1 COM 363576109 118,025 -75 -0.06 22,252 10.04 0.2506
2022-11-14 2022-09-30 13F/A-1 GALLAGHER AJ & CO USD1 COM 363576109 118,100 0 0.00 20,221 5.02 0.2495
2022-11-03 2022-09-30 13F GALLAGHER AJ & CO USD1 COM 363576109 118,100 0 20,221 0.2495
2022-08-12 2022-06-30 13F GALLAGHER AJ & CO USD1 COM 363576109 118,100 0 0.00 19,255 -6.62 0.2207
2022-05-11 2022-03-31 13F GALLAGHER AJ & CO USD1 COM 363576109 118,100 0 0.00 20,620 2.90 0.2104
2022-02-10 2021-12-31 13F GALLAGHER AJ & CO USD1 COM 363576109 118,100 -50 -0.04 20,038 14.09 0.1947
2021-11-04 2021-09-30 13F GALLAGHER AJ & CO USD1 COM 363576109 118,150 0 0.00 17,563 6.12 0.1890
2021-07-30 2021-06-30 13F GALLAGHER AJ & CO USD1 COM 363576109 118,150 -120 -0.10 16,550 12.15 0.1839
2021-05-14 2021-03-31 13F GALLAGHER AJ & CO USD1 COM 363576109 118,270 -130 -0.11 14,757 0.75 0.1890
2021-02-11 2020-12-31 13F GALLAGHER AJ & CO USD1 COM 363576109 118,400 -130 -0.11 14,647 17.04 0.2080
2020-11-13 2020-09-30 13F GALLAGHER AJ & CO USD1 COM 363576109 118,530 0 0.00 12,514 8.30 0.2141
2020-08-07 2020-06-30 13F GALLAGHER AJ & CO USD1 COM 363576109 118,530 0 0.00 11,555 19.60 0.2346
2020-05-04 2020-03-31 13F GALLAGHER AJ & CO USD1 COM 363576109 118,530 -190 -0.16 9,661 -14.55 0.2814
2020-02-11 2019-12-31 13F GALLAGHER AJ & CO USD1 COM 363576109 118,720 -150 -0.13 11,306 6.19 0.2976
2019-11-13 2019-09-30 13F GALLAGHER AJ & CO USD1 COM 363576109 118,870 0 0.00 10,647 2.26 0.3024
2019-08-12 2019-06-30 13F GALLAGHER AJ & CO USD1 COM 363576109 118,870 -580 -0.49 10,412 11.61 0.3260
2019-05-09 2019-03-31 13F GALLAGHER AJ & CO USD1 COM 363576109 119,450 0 0.00 9,329 5.98 0.3068
2019-02-12 2018-12-31 13F GALLAGHER AJ & CO USD1 COM 363576109 119,450 0 0.00 8,803 -1.00 0.3374
2018-10-12 2018-09-30 13F GALLAGHER AJ & CO USD1 COM 363576109 119,450 -215 -0.18 8,892 13.82 0.3021
2018-07-16 2018-06-30 13F GALLAGHER AJ & CO USD1 COM 363576109 119,665 -200 -0.17 7,812 -5.17 0.2960
2018-04-06 2018-03-31 13F GALLAGHER AJ & CO USD1 COM 363576109 119,865 -670 -0.56 8,238 8.01 0.3352
2018-01-24 2017-12-31 13F GALLAGHER AJ & CO USD1 COM 363576109 120,535 0 0.00 7,627 2.80 0.3104
2017-10-24 2017-09-30 13F GALLAGHER AJ & CO USD1 COM 363576109 120,535 0 0.00 7,419 7.51 0.3230
2017-08-10 2017-06-30 13F GALLAGHER AJ & CO USD1 COM 363576109 120,535 0 0.00 6,901 1.26 0.3075
2017-04-06 2017-03-31 13F GALLAGHER AJ & CO USD1 COM 363576109 120,535 0 0.00 6,815 8.81 0.3107
2017-02-02 2016-12-31 13F GALLAGHER AJ & CO USD1 COM 363576109 120,535 -560 -0.46 6,263 1.67 0.3139
2016-10-24 2016-09-30 13F GALLAGHER AJ & CO USD1 COM 363576109 121,095 0 0.00 6,160 6.87 0.3182
2016-08-03 2016-06-30 13F GALLAGHER AJ & CO USD1 COM 363576109 121,095 0 0.00 5,764 7.02 0.3176
2016-04-08 2016-03-31 13F GALLAGHER AJ & CO USD1 COM 363576109 121,095 -360 -0.30 5,386 17.62 0.3275
2016-01-19 2015-12-31 13F GALLAGHER AJ & CO USD1 COM 363576109 121,455 0 0.00 4,579 -8.68 0.2907
2015-10-27 2015-09-30 13F GALLAGHER AJ & CO USD1 COM 363576109 121,455 0 0.00 5,014 -12.72 0.3342
2015-08-05 2015-06-30 13F GALLAGHER AJ & CO USD1 COM 363576109 121,455 0 0.00 5,745 1.18 0.3731
2015-04-10 2015-03-31 13F GALLAGHER AJ & CO USD1 COM 363576109 121,455 -810 -0.66 5,678 -1.36 0.3757
2015-01-21 2014-12-31 13F GALLAGHER AJ & CO USD1 COM 363576109 122,265 0 0.00 5,756 3.79 0.3785
2014-10-23 2014-09-30 13F GALLAGHER AJ & CO US$1 COM 363576109 122,265 0 0.00 5,546 -2.67 0.3852
2014-07-02 2014-06-30 13F GALLAGHER AJ & CO US$1 COM 363576109 122,265 0 0.00 5,698 -2.05 0.4026
2014-04-11 2014-03-31 13F/A-1 GALLAGHER AJ & CO US$1 COM 363576109 122,265 -120 -0.10 5,817 1.27 0.4667
2014-04-10 2014-03-31 13F ISHARES TRUST Intl Developed Prop ETF COM 363576109 35,259 1,284
2014-01-10 2013-12-31 13F GALLAGHER AJ & CO US$1 COM 363576109 122,385 -1,005 -0.81 5,744 6.65 0.5731
2013-10-11 2013-09-30 13F GALLAGHER AJ & CO US$1 COM 363576109 123,390 0 0.00 5,386 -0.09 0.6275
2013-08-06 2013-06-30 13F GALLAGHER AJ & CO US$1 COM 363576109 123,390 123,390 5,391 0.7260
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.