Arthur J. Gallagher & Co.
MX ˙ BMV ˙ US3635761097
SecurityMX:AJG / Arthur J. Gallagher & Co.
InstitutionDimensional Fund Advisors Lp
Latest Disclosed Ownership853,192 shares
Latest Disclosed Value $ 184,780,946
Dimensional Fund Advisors Lp reports 5.91% increase in ownership of AJG / Arthur J. Gallagher & Co.

On May 7, 2026 - Dimensional Fund Advisors Lp filed a 13F-HR form disclosing ownership of 853,192 shares of Arthur J. Gallagher & Co. (MX:AJG) valued at $184,780,946 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 12, 2026 disclosing 805,604 shares of Arthur J. Gallagher & Co.. This represents a change in shares of 5.91% 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)
2026-05-07 2026-03-31 13F GALLAGHER ARTHUR J COM 363576109 853,192 47,588 5.91 184,781 -11.38 0.0384
2026-02-12 2025-12-31 13F GALLAGHER ARTHUR J COM 363576109 805,604 110,066 15.82 208,506 -3.20 0.0437
2025-11-12 2025-09-30 13F GALLAGHER ARTHUR J COM 363576109 695,538 -28,102 -3.88 215,404 -7.01 0.0462
2025-08-12 2025-06-30 13F GALLAGHER ARTHUR J COM 363576109 723,640 -12,527 -1.70 231,641 -8.85 0.0536
2025-05-13 2025-03-31 13F GALLAGHER ARTHUR J COM 363576109 736,167 7,257 1.00 254,121 22.82 0.0632
2025-02-13 2024-12-31 13F GALLAGHER ARTHUR J COM 363576109 728,910 48,431 7.12 206,906 8.07 0.0497
2024-11-07 2024-09-30 13F GALLAGHER ARTHUR J COM 363576109 680,479 7,023 1.04 191,454 9.63 0.0464
2024-08-09 2024-06-30 13F GALLAGHER ARTHUR J COM 363576109 673,456 64,864 10.66 174,640 14.76 0.0456
2024-05-10 2024-03-31 13F GALLAGHER ARTHUR J COM 363576109 608,592 7,975 1.33 152,172 12.67 0.0412
2024-02-07 2023-12-31 13F GALLAGHER ARTHUR J COM 363576109 600,617 -34,320 -5.41 135,060 -6.69 0.0394
2023-11-09 2023-09-30 13F GALLAGHER ARTHUR J COM 363576109 634,937 -75,293 -10.60 144,736 -7.18 0.0475
2023-08-09 2023-06-30 13F GALLAGHER ARTHUR J COM 363576109 710,230 7,930 1.13 155,927 16.06 0.0497
2023-05-12 2023-03-31 13F GALLAGHER ARTHUR J COM 363576109 702,300 -86,822 -11.00 134,352 90,677.70 0.0453
2023-02-09 2022-12-31 13F GALLAGHER ARTHUR J COM 363576109 789,122 -67,197 -7.85 149 -99.90 0.0440
2022-11-10 2022-09-30 13F GALLAGHER ARTHUR J COM 363576109 856,319 -440 -0.05 146,621 4.97 0.0563
2022-08-12 2022-06-30 13F GALLAGHER ARTHUR J COM 363576109 856,759 -585 -0.07 139,680 -6.69 0.0501
2022-05-13 2022-03-31 13F GALLAGHER ARTHUR J COM 363576109 857,344 14,791 1.76 149,689 4.71 0.0461
2022-02-09 2021-12-31 13F GALLAGHER ARTHUR J COM 363576109 842,553 -44,685 -5.04 142,952 8.38 0.0432
2021-11-12 2021-09-30 13F GALLAGHER ARTHUR J COM 363576109 887,238 -18,647 -2.06 131,900 3.94 0.0425
2021-08-12 2021-06-30 13F GALLAGHER ARTHUR J COM 363576109 905,885 -1,503 -0.17 126,903 12.08 0.0402
2021-05-14 2021-03-31 13F GALLAGHER ARTHUR J COM 363576109 907,388 16,257 1.82 113,221 2.71 0.0374
2021-03-08 2020-12-31 13F/A-2 GALLAGHER ARTHUR J COM 363576109 891,131 28,158 3.26 110,230 20.99 0.0398
2021-02-11 2020-12-31 13F GALLAGHER ARTHUR J COM 363576109 891,131 28,158 110,230 39,809.2170
2020-11-12 2020-09-30 13F GALLAGHER ARTHUR J COM 363576109 862,973 21,088 2.50 91,104 11.02 0.0386
2020-08-13 2020-06-30 13F GALLAGHER ARTHUR J COM 363576109 841,885 5,443 0.65 82,063 20.35 0.0361
2020-05-14 2020-03-31 13F GALLAGHER ARTHUR J COM 363576109 836,442 -11,146 -1.32 68,188 -15.52 0.0355
2020-02-14 2019-12-31 13F GALLAGHER ARTHUR J COM 363576109 847,588 -1,609 -0.19 80,714 6.12 0.0294
2019-11-12 2019-09-30 13F GALLAGHER ARTHUR J COM 363576109 849,197 -227 -0.03 76,058 2.24 0.0296
2019-08-13 2019-06-30 13F GALLAGHER ARTHUR J COM 363576109 849,424 11,813 1.41 74,392 13.73 0.0289
2019-08-12 2019-03-31 13F/A-2 GALLAGHER ARTHUR J COM 363576109 837,611 13,803 1.68 65,412 7.75 0.0261
2019-05-10 2019-03-31 13F GALLAGHER ARTHUR J COM 363576109 837,611 13,803 65,412
2019-02-26 2018-12-31 13F/A-1 GALLAGHER ARTHUR J COM 363576109 823,808 28,397 3.57 60,709 2.53 0.0275
2019-02-13 2018-12-31 13F GALLAGHER ARTHUR J COM 363576109 823,808 28,397 60,709
2018-11-13 2018-09-30 13F GALLAGHER ARTHUR J COM 363576109 795,411 28,434 3.71 59,210 18.26 0.0225
2018-08-10 2018-06-30 13F GALLAGHER ARTHUR J COM 363576109 766,977 901 0.12 50,068 -4.91 0.0200
2018-05-11 2018-03-31 13F GALLAGHER ARTHUR J COM 363576109 766,076 10,867 1.44 52,652 10.17 0.0219
2018-02-12 2017-12-31 13F GALLAGHER ARTHUR J COM 363576109 755,209 4,617 0.62 47,792 3.45 0.0198
2017-11-13 2017-09-30 13F GALLAGHER ARTHUR J COM 363576109 750,592 7,115 0.96 46,199 8.54 0.0202
2017-08-11 2017-06-30 13F GALLAGHER ARTHUR J COM 363576109 743,477 18,995 2.62 42,564 3.91 0.0197
2017-05-12 2017-03-31 13F GALLAGHER ARTHUR J COM 363576109 724,482 30,274 4.36 40,963 13.56 0.0196
2017-02-09 2016-12-31 13F GALLAGHER ARTHUR J COM 363576109 694,208 5,312 0.77 36,071 2.93 0.0180
2016-11-10 2016-09-30 13F GALLAGHER ARTHUR J COM 363576109 688,896 47,053 7.33 35,043 14.71 0.0189
2016-08-09 2016-06-30 13F GALLAGHER ARTHUR J COM 363576109 641,843 90,339 16.38 30,548 24.53 0.0176
2016-05-13 2016-03-31 13F GALLAGHER ARTHUR J COM 363576109 551,504 14,527 2.71 24,530 11.58 0.0147
2016-02-10 2015-12-31 13F GALLAGHER ARTHUR J COM 363576109 536,977 30,775 6.08 21,985 5.21 0.0137
2015-11-13 2015-09-30 13F GALLAGHER ARTHUR J COM 363576109 506,202 33,692 7.13 20,896 -6.51 0.0137
2015-08-14 2015-06-30 13F GALLAGHER ARTHUR J COM 363576109 472,510 179,187 61.09 22,350 62.97 0.0137
2015-05-14 2015-03-31 13F GALLAGHER ARTHUR J COM 363576109 293,323 4,075 1.41 13,714 0.68 0.0087
2015-02-06 2014-12-31 13F GALLAGHER ARTHUR J COM 363576109 289,248 24,821 9.39 13,621 13.57 0.0089
2014-11-13 2014-09-30 13F GALLAGHER ARTHUR J COM 363576109 264,427 -12,829 -4.63 11,994 -7.16 0.0085
2014-08-08 2014-06-30 13F GALLAGHER ARTHUR J COM 363576109 277,256 4,185 1.53 12,919 -0.55 0.0090
2014-05-14 2014-03-31 13F GALLAGHER ARTHUR J COM 363576109 273,071 2,683 0.99 12,990 2.37 0.0097
2014-02-12 2013-12-31 13F GALLAGHER ARTHUR J COM 363576109 270,388 898 0.33 12,689 7.87 0.0099
2013-11-13 2013-09-30 13F GALLAGHER ARTHUR J COM 363576109 269,490 10,442 4.03 11,763 3.93 0.0102
2013-08-15 2013-06-30 13F GALLAGHER ARTHUR J COM 363576109 259,048 259,048 11,318 0.0107
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.