Arthur J. Gallagher & Co.
MX ˙ BMV ˙ US3635761097
SecurityMX:AJG / Arthur J. Gallagher & Co.
InstitutionBlair William & Co/il
Latest Disclosed Ownership74,948 shares
Latest Disclosed Value $ 16,232,157
Blair William & Co/il reports 15.54% decrease in ownership of AJG / Arthur J. Gallagher & Co.

On May 8, 2026 - Blair William & Co/il filed a 13F-HR form disclosing ownership of 74,948 shares of Arthur J. Gallagher & Co. (MX:AJG) valued at $16,232,157 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 88,738 shares of Arthur J. Gallagher & Co.. This represents a change in shares of -15.54% 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)
2026-05-08 2026-03-31 13F GALLAGHER ARTHUR J COM 363576109 74,948 -13,790 -15.54 16,232 -29.32 0.0465
2026-02-17 2025-12-31 13F GALLAGHER ARTHUR J COM 363576109 88,738 -25,015 -21.99 22,965 -34.82 0.0616
2025-11-12 2025-09-30 13F GALLAGHER ARTHUR J COM 363576109 113,753 -3,216 -2.75 35,234 -5.90 0.0938
2025-07-24 2025-06-30 13F GALLAGHER ARTHUR J COM 363576109 116,969 18,620 18.93 37,444 10.28 0.1040
2025-05-09 2025-03-31 13F GALLAGHER ARTHUR J COM 363576109 98,349 5,850 6.32 33,954 29.32 0.1024
2025-02-12 2024-12-31 13F GALLAGHER ARTHUR J COM 363576109 92,499 3,465 3.89 26,256 4.81 0.0764
2024-11-12 2024-09-30 13F GALLAGHER ARTHUR J COM 363576109 89,034 1,474 1.68 25,052 10.33 0.0736
2024-08-12 2024-06-30 13F GALLAGHER ARTHUR J COM 363576109 87,560 892 1.03 22,705 4.78 0.0700
2024-05-09 2024-03-31 13F GALLAGHER ARTHUR J COM 363576109 86,668 -1,228 -1.40 21,671 9.64 0.0681
2024-02-12 2023-12-31 13F GALLAGHER ARTHUR J COM 363576109 87,896 6,920 8.55 19,766 7.09 0.0674
2023-11-09 2023-09-30 13F GALLAGHER ARTHUR J COM 363576109 80,976 -1,911 -2.31 18,457 1.41 0.0708
2023-08-11 2023-06-30 13F GALLAGHER ARTHUR J COM 363576109 82,887 1,369 1.68 18,200 16.70 0.0667
2023-05-12 2023-03-31 13F GALLAGHER ARTHUR J COM 363576109 81,518 -289 -0.35 15,595 1.12 0.0623
2023-02-10 2022-12-31 13F GALLAGHER ARTHUR J COM 363576109 81,807 887 1.10 15,424 11.32 0.0671
2022-11-09 2022-09-30 13F GALLAGHER ARTHUR J COM 363576109 80,920 -1,304 -1.59 13,855 3.35 0.0636
2022-08-10 2022-06-30 13F GALLAGHER ARTHUR J COM 363576109 82,224 -992 -1.19 13,406 -7.74 0.0595
2022-05-13 2022-03-31 13F GALLAGHER ARTHUR J COM 363576109 83,216 202 0.24 14,530 3.16 0.0509
2022-02-14 2021-12-31 13F GALLAGHER ARTHUR J COM 363576109 83,014 846 1.03 14,085 15.32 0.0442
2021-11-12 2021-09-30 13F GALLAGHER ARTHUR J COM 363576109 82,168 -363 -0.44 12,214 5.65 0.0416
2021-08-12 2021-06-30 13F GALLAGHER ARTHUR J COM 363576109 82,531 -1,448 -1.72 11,561 10.34 0.0401
2021-05-13 2021-03-31 13F GALLAGHER ARTHUR J COM 363576109 83,979 83 0.10 10,478 0.95 0.0395
2021-02-09 2020-12-31 13F GALLAGHER ARTHUR J COM 363576109 83,896 3,049 3.77 10,379 21.59 0.0381
2020-11-06 2020-09-30 13F GALLAGHER ARTHUR J COM 363576109 80,847 -4,943 -5.76 8,536 2.06 0.0362
2020-08-12 2020-06-30 13F GALLAGHER ARTHUR J COM 363576109 85,790 4,330 5.32 8,364 25.96 0.0399
2020-05-11 2020-03-31 13F GALLAGHER ARTHUR J COM 363576109 81,460 5,277 6.93 6,640 -8.48 0.0415
2020-02-13 2019-12-31 13F GALLAGHER ARTHUR J COM 363576109 76,183 3,030 4.14 7,255 10.73 0.0373
2019-11-12 2019-09-30 13F GALLAGHER ARTHUR J COM 363576109 73,153 917 1.27 6,552 3.56 0.0378
2019-08-13 2019-06-30 13F GALLAGHER ARTHUR J COM 363576109 72,236 34,138 89.61 6,327 112.67 0.0362
2019-05-14 2019-03-31 13F GALLAGHER ARTHUR J COM 363576109 38,098 6,853 21.93 2,975 29.18 0.0181
2019-02-14 2018-12-31 13F GALLAGHER ARTHUR J COM 363576109 31,245 10,095 47.73 2,303 46.32 0.0168
2018-11-13 2018-09-30 13F GALLAGHER ARTHUR J COM 363576109 21,150 12,123 134.30 1,574 167.23 0.0096
2018-08-13 2018-06-30 13F GALLAGHER ARTHUR J COM 363576109 9,027 2,982 49.33 589 41.93 0.0040
2018-05-15 2018-03-31 13F GALLAGHER ARTHUR J COM 363576109 6,045 2,018 50.11 415 62.75 0.0029
2018-02-14 2017-12-31 13F GALLAGHER ARTHUR J COM 363576109 4,027 0 0.00 255 2.82 0.0017
2017-11-13 2017-09-30 13F ARTHUR J GALLAGHER COM 363576109 4,027 123 3.15 248 10.71 0.0019
2017-08-04 2017-06-30 13F ARTHUR J GALLAGHER COM 363576109 3,904 3,904 224 0.0017
2015-02-05 2014-12-31 13F ARTHUR J GALLAGHER COM 363576109 0 -26,237 -100.00 0 -100.00
2014-11-04 2014-09-30 13F ARTHUR J GALLAGHER COM 363576109 26,237 17,300 193.58 1,190 186.06 0.0020
2014-08-01 2014-06-30 13F ARTHUR J GALLAGHER COM 363576109 8,937 -73 -0.81 416 -2.80 0.0007
2014-05-06 2014-03-31 13F ARTHUR J GALLAGHER COM 363576109 9,010 1,140 14.49 428 15.99 0.0007
2014-02-11 2013-12-31 13F ARTHUR J GALLAGHER COM 363576109 7,870 155 2.01 369 9.82 0.0006
2013-11-12 2013-09-30 13F ARTHUR J GALLAGHER COM 363576109 7,715 -165 -2.09 336 -2.33 0.0006
2013-08-07 2013-06-30 13F ARTHUR J GALLAGHER COM 363576109 7,880 7,880 344 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.