Arthur J. Gallagher & Co.
MX ˙ BMV ˙ US3635761097
SecurityMX:AJG / Arthur J. Gallagher & Co.
InstitutionCornerstone Capital, Inc.
Latest Disclosed Ownership103,213 shares
Latest Disclosed Value $ 22,353,872
Cornerstone Capital, Inc. reports 5.16% increase in ownership of AJG / Arthur J. Gallagher & Co.

On May 12, 2026 - Cornerstone Capital, Inc. filed a 13F-HR form disclosing ownership of 103,213 shares of Arthur J. Gallagher & Co. (MX:AJG) valued at $22,353,872 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 12, 2026 disclosing 98,145 shares of Arthur J. Gallagher & Co.. This represents a change in shares of 5.16% 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 103,213 5,068 5.16 22,354 -11.99 2.2326
2026-02-12 2025-12-31 13F GALLAGHER ARTHUR J COM 363576109 98,145 107 0.11 25,399 -16.36 2.5043
2025-11-10 2025-09-30 13F GALLAGHER ARTHUR J COM 363576109 98,038 -2,148 -2.14 30,366 -5.32 2.9714
2025-08-12 2025-06-30 13F GALLAGHER ARTHUR J COM 363576109 100,186 -4,956 -4.71 32,072 -11.65 3.3542
2025-05-13 2025-03-31 13F GALLAGHER ARTHUR J COM 363576109 105,142 -9,752 -8.49 36,299 11.31 3.9063
2025-02-13 2024-12-31 13F GALLAGHER ARTHUR J COM 363576109 114,894 -11,579 -9.16 32,613 -8.35 3.4335
2024-10-30 2024-09-30 13F GALLAGHER ARTHUR J COM 363576109 126,473 -562 -0.44 35,586 8.03 3.3228
2024-08-02 2024-06-30 13F GALLAGHER ARTHUR J COM 363576109 127,035 -343 -0.27 32,941 3.43 3.3222
2024-05-01 2024-03-31 13F GALLAGHER ARTHUR J COM 363576109 127,378 -9,111 -6.68 31,850 3.77 3.2668
2024-02-02 2023-12-31 13F GALLAGHER ARTHUR J COM 363576109 136,489 -6,120 -4.29 30,694 -5.57 3.3629
2023-11-13 2023-09-30 13F GALLAGHER ARTHUR J COM 363576109 142,609 -8,427 -5.58 32,505 -1.98 3.9171
2023-08-21 2023-06-30 13F GALLAGHER ARTHUR J COM 363576109 151,036 -19,565 -11.47 33,163 1.61 3.8359
2023-05-15 2023-03-31 13F GALLAGHER ARTHUR J COM 363576109 170,601 -3,942 -2.26 32,638 -0.82 3.9392
2023-02-13 2022-12-31 13F GALLAGHER ARTHUR J COM 363576109 174,543 25,031 16.74 32,908 28.55 4.2155
2022-10-27 2022-09-30 13F GALLAGHER ARTHUR J COM 363576109 149,512 -5,541 -3.57 25,599 1.26 3.5969
2022-08-15 2022-06-30 13F GALLAGHER ARTHUR J COM 363576109 155,053 -4,690 -2.94 25,280 -9.36 3.2393
2022-05-13 2022-03-31 13F GALLAGHER ARTHUR J COM 363576109 159,743 -20,228 -11.24 27,891 -8.66 3.1290
2022-02-11 2021-12-31 13F GALLAGHER ARTHUR J COM 363576109 179,971 -9,495 -5.01 30,536 8.42 3.2538
2021-11-09 2021-09-30 13F GALLAGHER ARTHUR J COM 363576109 189,466 -5,837 -2.99 28,164 2.95 3.2457
2021-08-13 2021-06-30 13F GALLAGHER ARTHUR J COM 363576109 195,303 -6,348 -3.15 27,358 8.74 3.1036
2021-05-17 2021-03-31 13F GALLAGHER ARTHUR J COM 363576109 201,651 -19,783 -8.93 25,160 -8.16 3.0432
2021-02-12 2020-12-31 13F GALLAGHER ARTHUR J COM 363576109 221,434 -16,719 -7.02 27,394 8.95 3.5243
2020-10-27 2020-09-30 13F GALLAGHER ARTHUR J COM 363576109 238,153 -5,232 -2.15 25,144 5.97 3.6229
2020-08-14 2020-06-30 13F GALLAGHER ARTHUR J COM 363576109 243,385 -57 -0.02 23,728 19.58 4.0432
2020-05-15 2020-03-31 13F GALLAGHER ARTHUR J COM 363576109 243,442 -59,694 -19.69 19,843 -31.26 4.1251
2020-02-10 2019-12-31 13F GALLAGHER ARTHUR J COM 363576109 303,136 -5,597 -1.81 28,868 4.39 4.0713
2019-11-13 2019-09-30 13F GALLAGHER ARTHUR J COM 363576109 308,733 -8,853 -2.79 27,653 -0.59 4.3020
2019-08-14 2019-06-30 13F GALLAGHER ARTHUR J COM 363576109 317,586 -6,703 -2.07 27,817 9.83 4.3630
2019-05-15 2019-03-31 13F GALLAGHER ARTHUR J COM 363576109 324,289 -12,981 -3.85 25,327 1.89 4.1880
2019-02-11 2018-12-31 13F GALLAGHER ARTHUR J COM 363576109 337,270 -2,560 -0.75 24,857 -1.74 4.4311
2018-11-13 2018-09-30 13F GALLAGHER ARTHUR J COM 363576109 339,830 -6,465 -1.87 25,297 11.90 3.8455
2018-08-13 2018-06-30 13F GALLAGHER ARTHUR J COM 363576109 346,295 -1,430 -0.41 22,606 -5.41 3.8410
2018-05-08 2018-03-31 13F GALLAGHER ARTHUR J COM 363576109 347,725 2,630 0.76 23,899 9.44 3.9358
2018-02-12 2017-12-31 13F GALLAGHER ARTHUR J COM 363576109 345,095 -7,115 -2.02 21,838 0.73 3.7066
2017-11-13 2017-09-30 13F GALLAGHER ARTHUR J COM 363576109 352,210 -1,175 -0.33 21,679 7.16 3.7928
2017-08-03 2017-06-30 13F GALLAGHER ARTHUR J COM 363576109 353,385 -3,030 -0.85 20,231 0.39 3.8487
2017-05-12 2017-03-31 13F GALLAGHER ARTHUR J COM 363576109 356,415 -14,862 -4.00 20,152 4.46 3.9414
2017-02-13 2016-12-31 13F GALLAGHER ARTHUR J COM 363576109 371,277 -710 -0.19 19,292 1.95 4.1235
2016-11-08 2016-09-30 13F GALLAGHER ARTHUR J COM 363576109 371,987 -908 -0.24 18,923 6.61 4.0874
2016-08-10 2016-06-30 13F GALLAGHER ARTHUR J COM 363576109 372,895 -780 -0.21 17,750 6.79 3.8689
2016-05-12 2016-03-31 13F GALLAGHER ARTHUR J COM 363576109 373,675 8,043 2.20 16,621 11.04 3.6651
2016-02-16 2015-12-31 13F GALLAGHER ARTHUR J COM 363576109 365,632 21,995 6.40 14,969 5.53 3.3828
2015-11-16 2015-09-30 13F GALLAGHER ARTHUR J COM 363576109 343,637 20,112 6.22 14,185 -7.31 3.5352
2015-08-14 2015-06-30 13F GALLAGHER ARTHUR J COM 363576109 323,525 19,706 6.49 15,303 7.74 3.5263
2015-05-15 2015-03-31 13F GALLAGHER ARTHUR J COM 363576109 303,819 3,757 1.25 14,204 0.55 3.7001
2015-02-17 2014-12-31 13F GALLAGHER ARTHUR J COM 363576109 300,062 6,885 2.35 14,127 6.23 3.7322
2014-11-14 2014-09-30 13F GALLAGHER ARTHUR J COM 363576109 293,177 -5,600 -1.87 13,299 -4.48 3.6871
2014-08-14 2014-06-30 13F GALLAGHER ARTHUR J COM 363576109 298,777 13,241 4.64 13,923 2.48 3.7514
2014-05-15 2014-03-31 13F GALLAGHER ARTHUR J COM 363576109 285,536 8,318 3.00 13,586 4.43 3.8931
2014-02-11 2013-12-31 13F GALLAGHER ARTHUR J COM 363576109 277,218 2,735 1.00 13,010 8.59 3.8154
2013-11-14 2013-09-30 13F GALLAGHER ARTHUR J COM 363576109 274,483 5,590 2.08 11,981 1.98 3.6545
2013-08-14 2013-06-30 13F GALLAGHER ARTHUR J COM 363576109 268,893 268,893 11,748 3.8524
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.