Arthur J. Gallagher & Co.
MX ˙ BMV ˙ US3635761097
SecurityMX:AJG / Arthur J. Gallagher & Co.
InstitutionBoston Private Wealth Llc
Latest Disclosed Ownership4,645 shares
Latest Disclosed Value $ 1,005,976
Boston Private Wealth Llc reports 12.09% decrease in ownership of AJG / Arthur J. Gallagher & Co.

On April 17, 2026 - Boston Private Wealth Llc filed a 13F-HR form disclosing ownership of 4,645 shares of Arthur J. Gallagher & Co. (MX:AJG) valued at $1,005,976 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 4, 2026 disclosing 5,284 shares of Arthur J. Gallagher & Co.. This represents a change in shares of -12.09% 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.

Upgrade to unlock premium data and export to Excel .

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)
2026-04-17 2026-03-31 13F ARTHUR J. GALLAGHER COM 363576109 4,645 -639 -12.09 1,006 -26.48 0.0177
2026-02-04 2025-12-31 13F ARTHUR J. GALLAGHER COM 363576109 5,284 -7,095 -57.31 1,368 -64.35 0.0806
2025-11-06 2025-09-30 13F ARTHUR J. GALLAGHER COM 363576109 12,379 76 0.62 3,834 -2.64 0.2063
2025-08-14 2025-06-30 13F ARTHUR J. GALLAGHER COM 363576109 12,303 12,303 3,939 0.2110
2025-05-14 2025-03-31 13F ARTHUR J. GALLAGHER COM 363576109 0 -8,810 -100.00 0 -100.00
2025-02-05 2024-12-31 13F ARTHUR J. GALLAGHER COM 363576109 8,810 8,810 2,501 0.0467
2024-10-18 2024-09-30 13F ARTHUR J. GALLAGHER COM 363576109 0 -7,706 -100.00 0 -100.00
2024-08-06 2024-06-30 13F ARTHUR J. GALLAGHER COM 363576109 7,706 828 12.04 1,998 16.23 0.0495
2024-05-15 2024-03-31 13F ARTHUR J. GALLAGHER COM 363576109 6,878 -430 -5.88 1,720 4.63 0.0383
2024-01-30 2023-12-31 13F ARTHUR J. GALLAGHER COM 363576109 7,308 -926 -11.25 1,643 -12.42 0.0400
2023-10-23 2023-09-30 13F ARTHUR J. GALLAGHER COM 363576109 8,234 -205 -2.43 1,877 1.24 0.0412
2023-07-24 2023-06-30 13F ARTHUR J. GALLAGHER COM 363576109 8,439 -2,915 -25.67 1,853 -14.69 0.0335
2023-05-12 2023-03-31 13F ARTHUR J. GALLAGHER COM 363576109 11,354 -668 -5.56 2,172 -4.15 0.0304
2023-02-10 2022-12-31 13F Gallagher Arthur J COM 363576109 12,022 857 7.68 2,267 18.58 0.0306
2022-11-09 2022-09-30 13F Gallagher Arthur J COM 363576109 11,165 949 9.29 1,911 14.71 0.0279
2022-08-16 2022-06-30 13F Gallagher Arthur J COM 363576109 10,216 -199 -1.91 1,666 -8.36 0.0256
2022-05-13 2022-03-31 13F Gallagher Arthur J COM 363576109 10,415 -116 -1.10 1,818 1.73 0.0243
2022-02-15 2021-12-31 13F Gallagher Arthur J COM 363576109 10,531 -480 -4.36 1,787 9.23 0.0293
2021-11-09 2021-09-30 13F Gallagher Arthur J COM 363576109 11,011 22 0.20 1,636 6.23 0.0210
2021-08-13 2021-06-30 13F Gallagher Arthur J COM 363576109 10,989 -143 -1.28 1,540 10.87 0.0195
2021-05-11 2021-03-31 13F Gallagher Arthur J COM 363576109 11,132 -80 -0.71 1,389 0.14 0.0193
2021-02-10 2020-12-31 13F Arthur J Gallagher COM 363576109 11,212 -557 -4.73 1,387 11.58 0.0204
2020-11-10 2020-09-30 13F Arthur J Gallagher COM 363576109 11,769 -1,152 -8.92 1,243 -1.35 0.0205
2020-08-05 2020-06-30 13F Arthur J Gallagher COM 363576109 12,921 -17,550 -57.60 1,260 -49.28 0.0234
2020-05-11 2020-03-31 13F Arthur J Gallagher COM 363576109 30,471 -26,086 -46.12 2,484 -53.88 0.0603
2020-02-13 2019-12-31 13F Arthur J Gallagher COM 363576109 56,557 -10,442 -15.59 5,386 -10.25 0.0980
2019-11-01 2019-09-30 13F Arthur J Gallagher COM 363576109 66,999 -16,479 -19.74 6,001 -17.93 0.1195
2019-07-10 2019-06-30 13F Arthur J Gallagher COM 363576109 83,478 -8,159 -8.90 7,312 2.17 0.2456
2019-05-14 2019-03-31 13F Arthur J Gallagher COM 363576109 91,637 -9,553 -9.44 7,157 -4.04 0.2827
2019-02-14 2018-12-31 13F Arthur J Gallagher COM 363576109 101,190 -8,254 -7.54 7,458 -8.46 0.3182
2018-11-13 2018-09-30 13F Arthur J Gallagher COM 363576109 109,444 -21,549 -16.45 8,147 -4.72 0.2881
2018-08-14 2018-06-30 13F Arthur J Gallagher COM 363576109 130,993 -18,028 -12.10 8,551 -16.51 0.3279
2018-05-11 2018-03-31 13F Arthur J Gallagher COM 363576109 149,021 -12,414 -7.69 10,242 0.25 0.3929
2018-02-13 2017-12-31 13F Arthur J Gallagher COM 363576109 161,435 -7,336 -4.35 10,216 -1.66 0.3843
2017-11-13 2017-09-30 13F Arthur J Gallagher COM 363576109 168,771 -1,785 -1.05 10,388 6.39 0.3995
2017-08-04 2017-06-30 13F Arthur J Gallagher COM 363576109 170,556 453 0.27 9,764 1.52 0.3831
2017-05-11 2017-03-31 13F Arthur J Gallagher COM 363576109 170,103 -7,443 -4.19 9,618 4.26 0.3831
2017-02-15 2016-12-31 13F Arthur J Gallagher COM 363576109 177,546 -8,491 -4.56 9,225 -2.53 0.3817
2016-11-15 2016-09-30 13F/A-1 Arthur J Gallagher COM 363576109 186,037 1,911 1.04 9,464 7.99 0.3849
2016-11-14 2016-09-30 13F Arthur J Gallagher COM 363576109 184,126 0 8,764 0.3576
2016-08-01 2016-06-30 13F Arthur J Gallagher COM 363576109 184,126 -402 -0.22 8,764 6.77 0.3576
2016-05-13 2016-03-31 13F Arthur J Gallagher COM 363576109 184,528 6,947 3.91 8,208 12.90 0.3342
2016-02-12 2015-12-31 13F Arthur J Gallagher COM 363576109 177,581 17,179 10.71 7,270 9.80 0.2868
2015-11-12 2015-09-30 13F Arthur J Gallagher COM 363576109 160,402 53,987 50.73 6,621 31.55 0.2566
2015-08-13 2015-06-30 13F Arthur J Gallagher COM 363576109 106,415 -828 -0.77 5,033 0.38 0.1666
2015-05-12 2015-03-31 13F Arthur J Gallagher COM 363576109 107,243 13,833 14.81 5,014 14.01 0.1619
2015-02-10 2014-12-31 13F Arthur J Gallagher COM 363576109 93,410 93,410 4,398 0.1422
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.