Arthur J. Gallagher & Co.
US ˙ NYSE ˙ US3635761097

SecurityAJG / Arthur J. Gallagher & Co.
InstitutionAssetmark, Inc
Latest Disclosed Ownership86,198 shares
Latest Disclosed Value $ 18,668,726
Assetmark, Inc reports 17.47% increase in ownership of AJG / Arthur J. Gallagher & Co.

On May 6, 2026 - Assetmark, Inc filed a 13F-HR form disclosing ownership of 86,198 shares of Arthur J. Gallagher & Co. (US:AJG) valued at $18,668,763 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 23, 2026 disclosing 73,376 shares of Arthur J. Gallagher & Co.. This represents a change in shares of 17.47% during the quarter. The current value of the position is $17,455,095 USD.

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)
2026-05-06 2026-03-31 13F GALLAGHER ARTHUR J COM 363576109 86,198 12,822 17.47 18,669 -1.69 0.0381
2026-01-23 2025-12-31 13F GALLAGHER ARTHUR J COM 363576109 73,376 104 0.14 18,989 -16.33 0.0387
2025-11-06 2025-09-30 13F GALLAGHER ARTHUR J COM 363576109 73,272 32,705 80.62 22,695 74.77 0.0487
2025-08-04 2025-06-30 13F GALLAGHER ARTHUR J COM 363576109 40,567 11,553 39.82 12,986 29.65 0.0307
2025-05-06 2025-03-31 13F GALLAGHER ARTHUR J COM 363576109 29,014 13,528 87.36 10,017 127.90 0.0275
2025-02-06 2024-12-31 13F GALLAGHER ARTHUR J COM 363576109 15,486 2,397 18.31 4,396 19.36 0.0119
2024-11-01 2024-09-30 13F GALLAGHER ARTHUR J COM 363576109 13,089 854 6.98 3,683 16.08 0.0105
2024-08-13 2024-06-30 13F GALLAGHER ARTHUR J COM 363576109 12,235 1,954 19.01 3,173 23.42 0.0098
2024-05-07 2024-03-31 13F GALLAGHER ARTHUR J COM 363576109 10,281 3,241 46.04 2,571 62.35 0.0084
2024-02-09 2023-12-31 13F GALLAGHER ARTHUR J COM 363576109 7,040 2,832 67.30 1,583 65.07 0.0057
2023-10-27 2023-09-30 13F GALLAGHER ARTHUR J COM 363576109 4,208 -14 -0.33 959 3.45 0.0038
2023-08-11 2023-06-30 13F GALLAGHER ARTHUR J & CO COM COM 363576109 4,222 -1,537 -26.69 927 -15.80 0.0036
2023-05-05 2023-03-31 13F GALLAGHER ARTHUR J & CO COM COM 363576109 5,759 519 9.90 1,102 11.55 0.0046
2023-02-10 2022-12-31 13F GALLAGHER ARTHUR J COM 363576109 5,240 786 17.65 988 29.36 0.0043
2022-11-01 2022-09-30 13F GALLAGHER ARTHUR J COM 363576109 4,454 1,720 62.91 763 71.08 0.0036
2022-08-03 2022-06-30 13F GALLAGHER ARTHUR J & CO COM COM 363576109 2,734 1,585 137.95 446 121.89 0.0020
2022-05-13 2022-03-31 13F GALLAGHER ARTHUR J & CO COM COM 363576109 1,149 728 172.92 201 183.10 0.0008
2022-02-14 2021-12-31 13F GALLAGHER ARTHUR J & CO COM COM 363576109 421 336 395.29 71 446.15 0.0003
2021-11-12 2021-09-30 13F GALLAGHER ARTHUR J & CO COM COM 363576109 85 85 13 0.0001
2021-02-10 2020-12-31 13F GALLAGHER ARTHUR J & CO COM COM 363576109 0 -5 -100.00 0 -100.00
2020-11-13 2020-09-30 13F GALLAGHER ARTHUR J & CO COM COM 363576109 5 0 0.00 1 0.0000
2020-08-11 2020-06-30 13F GALLAGHER ARTHUR J & CO COM COM 363576109 5 -2,345 -99.79 0 -100.00
2020-05-12 2020-03-31 13F GALLAGHER ARTHUR J & CO COM COM 363576109 2,350 -302 -11.39 192 -24.11 0.0016
2020-02-11 2019-12-31 13F GALLAGHER ARTHUR J & CO COM COM 363576109 2,652 1,431 117.20 253 132.11 0.0019
2019-11-13 2019-09-30 13F GALLAGHER ARTHUR J & CO COM COM 363576109 1,221 110 9.90 109 12.37 0.0009
2019-08-14 2019-06-30 13F GALLAGHER ARTHUR J & CO COM COM 363576109 1,111 275 32.89 97 49.23 0.0008
2019-05-14 2019-03-31 13F GALLAGHER ARTHUR J & CO COM COM 363576109 836 836 -24.75 65 -32.99 0.0006
2018-05-16 2018-03-31 13F GALLAGHER ARTHUR J & CO COM COM 363576109 0 -151 -100.00 0 -100.00
2018-02-13 2017-12-31 13F GALLAGHER ARTHUR J & CO COM COM 363576109 151 96 174.55 10 233.33 0.0001
2017-11-08 2017-09-30 13F GALLAGHER ARTHUR J & CO COM COM 363576109 55 31 129.17 3 200.00 0.0000
2017-08-14 2017-06-30 13F GALLAGHER ARTHUR J & CO COM COM 363576109 24 24 -56.36 1 -66.67 0.0000
2017-09-14 2016-03-31 13F/A-1 GALLAGHER ARTHUR J & CO COM COM 363576109 0 -20 -100.00 0 -100.00
2017-09-14 2015-12-31 13F/A-1 GALLAGHER ARTHUR J & CO COM COM 363576109 20 11 122.22 1 0.0000
2016-02-12 2015-12-31 13F GALLAGHER ARTHUR J & CO COM COM 363576109 20 11 1
2016-01-05 2015-09-30 13F/A-1 GALLAGHER ARTHUR J & CO COM COM 363576109 9 9 0 0.0000
2015-11-10 2015-09-30 13F GALLAGHER ARTHUR J & CO COM COM 363576109 9 0
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.