아서 J. 갤러거 앤 컴퍼니
MX ˙ BMV ˙ US3635761097
SecurityMX:AJG / Arthur J. Gallagher & Co.
InstitutionRenaissance Technologies Llc
ManagerJames Simons
Latest Disclosed Ownership76,600 shares
Latest Disclosed Value $ 16,590,028
Renaissance Technologies Llc reports 1,673.15% increase in ownership of AJG / Arthur J. Gallagher & Co.

On May 14, 2026 - Renaissance Technologies Llc filed a 13F-HR form disclosing ownership of 76,600 shares of Arthur J. Gallagher & Co. (MX:AJG) valued at $16,590,028 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 12, 2026 disclosing 4,320 shares of Arthur J. Gallagher & Co.. This represents a change in shares of 1,673.15% 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)
2026-05-14 2026-03-31 13F GALLAGHER ARTHUR J COM 363576109 76,600 72,280 1,673.15 16,590 1,385.23 0.0260
2026-02-12 2025-12-31 13F GALLAGHER ARTHUR J COM 363576109 4,320 -396,180 -98.92 1,118 -99.10 0.0017
2025-11-13 2025-09-30 13F GALLAGHER ARTHUR J COM 363576109 400,500 50,900 14.56 124,051 10.85 0.1638
2025-08-13 2025-06-30 13F GALLAGHER ARTHUR J COM 363576109 349,600 30,600 9.59 111,914 1.62 0.1489
2025-05-14 2025-03-31 13F GALLAGHER ARTHUR J COM 363576109 319,000 145,800 84.18 110,132 124.02 0.1667
2025-02-13 2024-12-31 13F GALLAGHER ARTHUR J COM 363576109 173,200 82,500 90.96 49,163 92.64 0.0728
2024-11-13 2024-09-30 13F GALLAGHER ARTHUR J COM 363576109 90,700 90,700 25,520 0.0384
2024-08-09 2024-06-30 13F GALLAGHER ARTHUR J COM 363576109 0 -76,400 -100.00 0 -100.00
2024-05-13 2024-03-31 13F GALLAGHER ARTHUR J COM 363576109 76,400 76,400 19 0.0300
2023-11-14 2023-09-30 13F GALLAGHER ARTHUR J COM 363576109 0 -20,800 -100.00 0 -100.00
2023-08-11 2023-06-30 13F GALLAGHER ARTHUR J COM 363576109 20,800 20,800 5 0.0066
2022-11-14 2022-09-30 13F GALLAGHER ARTHUR J COM 363576109 0 -125,200 -100.00 0 -100.00
2022-08-12 2022-06-30 13F GALLAGHER ARTHUR J COM 363576109 125,200 -149,800 -54.47 20,413 -57.49 0.0242
2022-05-13 2022-03-31 13F GALLAGHER ARTHUR J COM 363576109 275,000 1,900 0.70 48,015 3.62 0.0563
2022-02-11 2021-12-31 13F GALLAGHER ARTHUR J COM 363576109 273,100 -455,900 -62.54 46,337 -57.24 0.0576
2021-11-12 2021-09-30 13F GALLAGHER ARTHUR J COM 363576109 729,000 412,710 130.48 108,366 144.59 0.1400
2021-08-13 2021-06-30 13F GALLAGHER ARTHUR J COM 363576109 316,290 316,290 44,306 0.0553
2021-02-10 2020-12-31 13F GALLAGHER ARTHUR J COM 363576109 0 -184,300 -100.00 0 -100.00
2020-11-13 2020-09-30 13F GALLAGHER ARTHUR J COM 363576109 184,300 200 0.11 19,458 8.41 0.0194
2020-08-13 2020-06-30 13F GALLAGHER ARTHUR J COM 363576109 184,100 88,700 92.98 17,948 130.81 0.0155
2020-05-14 2020-03-31 13F GALLAGHER ARTHUR J COM 363576109 95,400 7,600 8.66 7,776 -7.00 0.0076
2020-02-13 2019-12-31 13F GALLAGHER ARTHUR J COM 363576109 87,800 -54,500 -38.30 8,361 -34.40 0.0064
2019-11-13 2019-09-30 13F GALLAGHER ARTHUR J COM 363576109 142,300 -94,400 -39.88 12,746 -38.52 0.0108
2019-08-12 2019-06-30 13F GALLAGHER ARTHUR J COM 363576109 236,700 -130,700 -35.57 20,733 -27.74 0.0183
2019-05-14 2019-03-31 13F GALLAGHER ARTHUR J COM 363576109 367,400 367,400 55.22 28,694 38.40 0.0261
2019-02-12 2018-12-31 13F GALLAGHER ARTHUR J COM 363576109 0 -137,100 -100.00 0 -100.00
2018-11-13 2018-09-30 13F GALLAGHER ARTHUR J COM 363576109 137,100 -153,300 -52.79 10,206 -46.16 0.0105
2018-08-13 2018-06-30 13F/A-1 GALLAGHER ARTHUR J COM 363576109 290,400 -141,900 -32.82 18,957 -36.20 0.0207
2018-08-13 2018-06-30 13F GALLAGHER ARTHUR J COM 363576109 432,300 29,712
2018-05-14 2018-03-31 13F GALLAGHER ARTHUR J COM 363576109 432,300 102,700 31.16 29,712 42.46 0.0325
2018-02-13 2017-12-31 13F GALLAGHER ARTHUR J COM 363576109 329,600 11,200 3.52 20,857 6.42 0.0230
2017-11-13 2017-09-30 13F GALLAGHER ARTHUR J COM 363576109 318,400 -89,600 -21.96 19,598 -16.10 0.0231
2017-08-11 2017-06-30 13F GALLAGHER ARTHUR J COM 363576109 408,000 368,300 927.71 23,358 940.45 0.0298
2017-05-12 2017-03-31 13F GALLAGHER ARTHUR J COM 363576109 39,700 -433,500 -91.61 2,245 -90.87 0.0031
2017-02-13 2016-12-31 13F GALLAGHER ARTHUR J COM 363576109 473,200 473,200 1,091.94 24,587 995.19 0.0389
2016-11-14 2016-09-30 13F GALLAGHER ARTHUR J COM 363576109 0 -64,900 -100.00 0 -100.00
2016-08-12 2016-06-30 13F GALLAGHER ARTHUR J COM 363576109 64,900 -100,800 -60.83 3,089 -58.09 0.0059
2016-05-13 2016-03-31 13F GALLAGHER ARTHUR J COM 363576109 165,700 88,300 114.08 7,370 132.57 0.0140
2016-02-11 2015-12-31 13F GALLAGHER ARTHUR J COM 363576109 77,400 -432,700 -84.83 3,169 -84.95 0.0069
2015-11-12 2015-09-30 13F GALLAGHER ARTHUR J COM 363576109 510,100 411,700 418.39 21,057 352.45 0.0502
2015-08-14 2015-06-30 13F GALLAGHER ARTHUR J COM 363576109 98,400 -436,600 -81.61 4,654 -81.39 0.0106
2015-05-13 2015-03-31 13F GALLAGHER ARTHUR J COM 363576109 535,000 -165,000 -23.57 25,011 -24.11 0.0533
2015-02-13 2014-12-31 13F GALLAGHER ARTHUR J COM 363576109 700,000 583,200 499.32 32,956 522.05 0.0796
2014-11-12 2014-09-30 13F GALLAGHER ARTHUR J COM 363576109 116,800 112,300 2,495.56 5,298 2,422.86 0.0145
2014-08-13 2014-06-30 13F GALLAGHER ARTHUR J COM 363576109 4,500 -158,901 -97.25 210 -97.30 0.0005
2014-05-14 2014-03-31 13F GALLAGHER ARTHUR J COM 363576109 163,401 -372,399 -69.50 7,775 -69.08 0.0186
2014-02-14 2013-12-31 13F GALLAGHER ARTHUR J COM 363576109 535,800 -46,900 -8.05 25,145 -1.14 0.0602
2013-11-13 2013-09-30 13F GALLAGHER ARTHUR J COM 363576109 582,700 281,300 93.33 25,435 93.16 0.0617
2013-08-12 2013-06-30 13F GALLAGHER ARTHUR J COM 363576109 301,400 301,400 13,168 0.0345
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.