Arthur J. Gallagher & Co.
MX ˙ BMV ˙ US3635761097
SecurityMX:AJG / Arthur J. Gallagher & Co.
InstitutionDearborn Partners Llc
Latest Disclosed Ownership125,858 shares
Latest Disclosed Value $ 27,258,408
Dearborn Partners Llc reports 6.03% decrease in ownership of AJG / Arthur J. Gallagher & Co.

On May 12, 2026 - Dearborn Partners Llc filed a 13F-HR form disclosing ownership of 125,858 shares of Arthur J. Gallagher & Co. (MX:AJG) valued at $27,258,408 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 11, 2026 disclosing 133,936 shares of Arthur J. Gallagher & Co.. This represents a change in shares of -6.03% 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 Arthur J. Gallagher COM 363576109 125,858 -8,078 -6.03 27,258 -21.36 1.4258
2026-02-11 2025-12-31 13F Arthur J. Gallagher COM 363576109 133,936 7,946 6.31 34,661 -11.18 1.7309
2025-11-10 2025-09-30 13F Arthur J. Gallagher COM 363576109 125,990 1,100 0.88 39,024 -2.39 1.8298
2025-08-14 2025-06-30 13F Arthur J. Gallagher COM 363576109 124,890 1,328 1.07 39,980 -6.28 1.8925
2025-05-08 2025-03-31 13F Arthur J. Gallagher COM 363576109 123,562 -19,804 -13.81 42,659 4.83 2.0478
2025-02-07 2024-12-31 13F Arthur J. Gallagher COM 363576109 143,366 -2,183 -1.50 40,694 -0.63 1.7051
2024-11-06 2024-09-30 13F Arthur J. Gallagher COM 363576109 145,549 -6,333 -4.17 40,953 3.98 1.6623
2024-07-26 2024-06-30 13F Arthur J. Gallagher COM 363576109 151,882 -22,409 -12.86 39,385 -9.63 1.7029
2024-05-08 2024-03-31 13F Arthur J. Gallagher COM 363576109 174,291 -37,476 -17.70 43,580 -8.49 1.8709
2024-01-26 2023-12-31 13F Arthur J. Gallagher COM 363576109 211,767 -43,809 -17.14 47,622 -18.25 1.7347
2023-11-01 2023-09-30 13F Arthur J. Gallagher COM 363576109 255,576 1,074 0.42 58,253 4.24 2.2859
2023-08-03 2023-06-30 13F Arthur J. Gallagher COM 363576109 254,502 -737 -0.29 55,881 14.44 2.1383
2023-05-04 2023-03-31 13F Arthur J Gallagher COM 363576109 255,239 -2,211 -0.86 48,830 0.60 1.9209
2023-02-02 2022-12-31 13F Arthur J Gallagher COM 363576109 257,450 -46,603 -15.33 48,540 -6.76 1.9591
2022-11-21 2022-09-30 13F/A-1 Arthur J Gallagher COM 363576109 304,053 -1,432 -0.47 52,060 4.53 2.2963
2022-10-25 2022-09-30 13F Arthur J Gallagher COM 363576109 304,053 -1,432 52,060 2.1464
2022-07-20 2022-06-30 13F Arthur J Gallagher COM 363576109 305,485 -2,677 -0.87 49,806 -7.43 2.1037
2022-05-04 2022-03-31 13F Arthur J Gallagher COM 363576109 308,162 -45,332 -12.82 53,805 -10.29 2.0405
2022-01-28 2021-12-31 13F Arthur J Gallagher COM 363576109 353,494 -2,537 -0.71 59,977 13.33 2.1745
2021-10-27 2021-09-30 13F Arthur J Gallagher COM 363576109 356,031 303 0.09 52,924 6.21 2.1496
2021-07-26 2021-06-30 13F Arthur J Gallagher COM 363576109 355,728 -73,228 -17.07 49,830 -6.90 2.0037
2021-04-29 2021-03-31 13F Arthur J Gallagher COM 363576109 428,956 12,997 3.12 53,521 4.01 2.2806
2021-01-27 2020-12-31 13F Arthur J Gallagher COM 363576109 415,959 7,094 1.74 51,458 19.20 2.3425
2020-10-20 2020-09-30 13F Arthur J Gallagher COM 363576109 408,865 -96 -0.02 43,168 8.27 2.1493
2020-07-30 2020-06-30 13F Arthur J Gallagher COM 363576109 408,961 -12,319 -2.92 39,870 16.11 2.1545
2020-05-11 2020-03-31 13F Arthur J Gallagher COM 363576109 421,280 11,993 2.93 34,339 -11.90 2.1298
2020-01-28 2019-12-31 13F Arthur J Gallagher COM 363576109 409,287 22,544 5.83 38,976 12.51 1.9851
2019-10-29 2019-09-30 13F Arthur J Gallagher COM 363576109 386,743 6,807 1.79 34,641 4.09 2.0030
2019-07-29 2019-06-30 13F Arthur J Gallagher COM 363576109 379,936 11,451 3.11 33,279 15.64 2.0321
2019-05-01 2019-03-31 13F Arthur J Gallagher COM 363576109 368,485 3,552 0.97 28,779 7.00 1.9206
2019-02-04 2018-12-31 13F Arthur J Gallagher COM 363576109 364,933 172,650 89.79 26,896 87.90 2.0780
2018-10-24 2018-09-30 13F Arthur J Gallagher COM 363576109 192,283 383 0.20 14,314 14.27 1.0027
2018-08-14 2018-06-30 13F Arthur J Gallagher COM 363576109 191,900 -5,576 -2.82 12,527 -7.71 0.9791
2018-05-01 2018-03-31 13F Arthur J Gallagher COM 363576109 197,476 -4,291 -2.13 13,573 6.30 1.0474
2018-02-02 2017-12-31 13F Arthur J Gallagher COM 363576109 201,767 -503 -0.25 12,768 2.55 0.9193
2017-11-13 2017-09-30 13F Arthur J Gallagher COM 363576109 202,270 995 0.49 12,450 8.04 0.9160
2017-08-09 2017-06-30 13F Arthur J Gallagher COM 363576109 201,275 9,154 4.76 11,523 6.08 0.8514
2017-05-15 2017-03-31 13F Arthur J Gallagher COM 363576109 192,121 5,653 3.03 10,863 12.12 0.8450
2017-01-26 2016-12-31 13F Arthur J Gallagher COM 363576109 186,468 5,657 3.13 9,689 5.34 0.8100
2016-10-24 2016-09-30 13F Arthur J Gallagher COM 363576109 180,811 11,415 6.74 9,198 14.08 0.7760
2016-07-18 2016-06-30 13F Arthur J Gallagher COM 363576109 169,396 1,707 1.02 8,063 8.10 0.6996
2016-04-19 2016-03-31 13F Arthur J Gallagher COM 363576109 167,689 8,371 5.25 7,459 14.37 0.6936
2016-01-21 2015-12-31 13F Arthur J Gallagher COM 363576109 159,318 14,341 9.89 6,522 8.97 0.6071
2015-10-19 2015-09-30 13F Arthur J Gallagher COM 363576109 144,977 6,412 4.63 5,985 -8.68 0.5997
2015-08-13 2015-06-30 13F Arthur J Gallagher COM 363576109 138,565 -515 -0.37 6,554 0.80 0.6318
2015-04-21 2015-03-31 13F Arthur J Gallagher COM 363576109 139,080 139,080 6,502 0.5685
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.