Arthur J. Gallagher & Co.
MX ˙ BMV ˙ US3635761097
SecurityMX:AJG / Arthur J. Gallagher & Co.
InstitutionM&t Bank Corp
Latest Disclosed Ownership21,982 shares
Latest Disclosed Value $ 4,760,862
M&t Bank Corp ownership in AJG / Arthur J. Gallagher & Co.

On May 12, 2026 - M&t Bank Corp filed a 13F-HR form disclosing ownership of 21,982 shares of Arthur J. Gallagher & Co. (MX:AJG) valued at $4,760,862 USD as of March 31, 2026. The entity filed a previous 13F-HR/A on January 30, 2026 disclosing 22,873 shares of Arthur J. Gallagher & Co.. This represents a change in shares of -3.90% during the quarter.

M&t Bank Corp has a history of taking positions in derivatives of the underlying security (AJG) in the form of stock options. The firm currently holds call options representing 0 of underlying shares valued at $0 USD .

Note: prior versions of this page mistakenly stated that the share values represented the number of options, not the number of underlying shares. For more information on the data backing these reports, please see the SEC document Frequently Asked Questions About Form 13F.

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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Institutional Put/Call Ratios
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In addition to reporting standard equity and debt issues, institutions with more than 100MM assets under management must also disclose their put and call option holdings. Since put options generally indicate negative sentiment, and call options indicate positive sentiment, we can get a sense of the overall institutional sentiment by plotting the ratio of puts to calls. The chart to the right plots the historical put/call ratio for this instrument.

Using Put/Call Ratio as an indicator of investor sentiment overcomes one of the key deficiencies of using total institutional ownership, which is that a significant amount of assets under management are invested passively to track indices. Passively-managed funds do not typically buy options, so the put/call ratio indicator more closely tracks the sentiment of actively-managed funds.

MX:AJG / Arthur J. Gallagher & Co. Historical Put/Call Ratio
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 21,982 -891 -3.90 4,761 -19.57 0.0039
2026-01-30 2025-12-31 13F/A-1 GALLAGHER ARTHUR J COM 363576109 22,873 1,650 7.77 5,919 -9.98 0.0190
2026-01-28 2025-12-31 13F GALLAGHER ARTHUR J COM 363576109 588,023 566,800 70,271 0.0419
2025-11-14 2025-09-30 13F GALLAGHER ARTHUR J COM 363576109 21,223 -9,121 -30.06 6,574 -32.32 0.0221
2025-08-13 2025-06-30 13F GALLAGHER ARTHUR J COM 363576109 30,344 -134 -0.44 9,714 -7.68 0.0334
2025-04-30 2025-03-31 13F GALLAGHER ARTHUR J COM 363576109 30,478 519 1.73 10,522 23.72 0.0383
2025-02-06 2024-12-31 13F GALLAGHER ARTHUR J COM 363576109 29,959 1,886 6.72 8,504 7.66 0.0285
2024-11-19 2024-09-30 13F/A-1 GALLAGHER ARTHUR J COM 363576109 28,073 -1,249 -4.26 7,899 3.89 0.0260
2024-11-15 2024-09-30 13F GALLAGHER ARTHUR J COM 363576109 28,073 -1,249 7,899 0.0048
2024-07-31 2024-06-30 13F GALLAGHER ARTHUR J COM 363576109 29,322 -4,257 -12.68 7,603 -9.44 0.0259
2024-05-07 2024-03-31 13F GALLAGHER ARTHUR J COM 363576109 33,579 -47,429 -58.55 8,396 -53.91 0.0292
2024-02-06 2023-12-31 13F GALLAGHER ARTHUR J COM 363576109 81,008 -12,405 -13.28 18,217 -14.44 0.0669
2023-11-02 2023-09-30 13F GALLAGHER ARTHUR J COM 363576109 93,413 -4,793 -4.88 21,292 -1.26 0.0849
2023-08-09 2023-06-30 13F GALLAGHER ARTHUR J COM 363576109 98,206 721 0.74 21,563 15.62 0.0805
2023-05-11 2023-03-31 13F GALLAGHER ARTHUR J COM 363576109 97,485 49,364 102.58 18,651 105.58 0.0722
2023-02-13 2022-12-31 13F/A-1 GALLAGHER ARTHUR J COM 363576109 48,121 -4,976 -9.37 9,073 -0.21 0.0365
2023-02-13 2022-12-31 13F GXO LOGISTICS COMMON STOCK 363576109 55,195 2,098 8,409 0.0338
2022-11-17 2022-09-30 13F/A-1 GALLAGHER ARTHUR J COM 363576109 53,097 -3,740 -6.58 9,091 71.85 0.0404
2022-11-14 2022-09-30 13F GALLAGHER ARTHUR J COM 363576109 53,097 -3,740 8,841 0.0075
2022-08-05 2022-06-30 13F GALLAGHER ARTHUR J COM 363576109 56,837 23,735 71.70 5,290 -8.48 0.0249
2022-05-09 2022-03-31 13F GALLAGHER ARTHUR J COM 363576109 33,102 631 1.94 5,780 4.90 0.0255
2022-02-07 2021-12-31 13F GALLAGHER ARTHUR J COM 363576109 32,471 331 1.03 5,510 15.34 0.0231
2021-10-28 2021-09-30 13F GALLAGHER ARTHUR J COM 363576109 32,140 -172 -0.53 4,777 5.55 0.0215
2021-08-13 2021-06-30 13F GALLAGHER ARTHUR J COM 363576109 32,312 -7,325 -18.48 4,526 -8.49 0.0199
2021-05-06 2021-03-31 13F GALLAGHER ARTHUR J COM 363576109 39,637 -3,025 -7.09 4,946 -6.29 0.0213
2021-02-12 2020-12-31 13F GALLAGHER ARTHUR J COM 363576109 42,662 798 1.91 5,278 19.41 0.0232
2020-11-06 2020-09-30 13F GALLAGHER ARTHUR J COM 363576109 41,864 -6,145 -12.80 4,420 -5.58 0.0217
2020-07-29 2020-06-30 13F GALLAGHER ARTHUR J COM 363576109 48,009 -1,007 -2.05 4,681 17.17 0.0251
2020-05-14 2020-03-31 13F GALLAGHER ARTHUR J COM 363576109 49,016 -16,521 -25.21 3,995 -35.99 0.0236
2020-02-07 2019-12-31 13F GALLAGHER ARTHUR J COM 363576109 65,537 -2,385 -3.51 6,241 2.60 0.0293
2019-11-12 2019-09-30 13F GALLAGHER ARTHUR J COM 363576109 67,922 -37 -0.05 6,083 2.22 0.0303
2019-08-12 2019-06-30 13F GALLAGHER ARTHUR J COM 363576109 67,959 9,232 15.72 5,951 29.71 0.0311
2019-05-15 2019-03-31 13F GALLAGHER ARTHUR J COM 363576109 58,727 -216 -0.37 4,588 5.62 0.0240
2019-02-01 2018-12-31 13F GALLAGHER ARTHUR J COM 363576109 58,943 -443 -0.75 4,344 -1.72 0.0249
2018-11-09 2018-09-30 13F GALLAGHER ARTHUR J COM 363576109 59,386 -2,121 -3.45 4,420 10.09 0.0221
2018-08-10 2018-06-30 13F GALLAGHER ARTHUR J COM 363576109 61,507 -212 -0.34 4,015 -5.40 0.0216
2018-05-04 2018-03-31 13F GALLAGHER ARTHUR J COM 363576109 61,719 202 0.33 4,244 9.02 0.0228
2018-02-06 2017-12-31 13F GALLAGHER ARTHUR J COM 363576109 61,517 455 0.75 3,893 3.56 0.0204
2017-11-13 2017-09-30 13F GALLAGHER ARTHUR J COM 363576109 61,062 -124 -0.20 3,759 7.31 0.0204
2017-08-11 2017-06-30 13F GALLAGHER ARTHUR J COM 363576109 61,186 -3,234 -5.02 3,503 -3.84 0.0207
2017-05-10 2017-03-31 13F GALLAGHER ARTHUR J COM 363576109 64,420 -1,189 -1.81 3,643 6.83 0.0220
2017-02-14 2016-12-31 13F GALLAGHER ARTHUR J COM 363576109 65,609 24,210 58.48 3,410 61.92 0.0212
2016-11-04 2016-09-30 13F GALLAGHER ARTHUR J COM 363576109 41,399 -1,114 -2.62 2,106 4.10 0.0134
2016-08-04 2016-06-30 13F GALLAGHER ARTHUR J COM 363576109 42,513 212 0.50 2,023 7.49 0.0136
2016-05-11 2016-03-31 13F GALLAGHER ARTHUR J COM 363576109 42,301 -12,770 -23.19 1,882 -16.50 0.0127
2016-02-12 2015-12-31 13F GALLAGHER ARTHUR J COM 363576109 55,071 -408,676 -88.12 2,254 -88.23 0.0150
2015-11-13 2015-09-30 13F GALLAGHER ARTHUR J COM 363576109 463,747 -713 -0.15 19,143 -12.86 0.1304
2015-08-14 2015-06-30 13F GALLAGHER ARTHUR J COM 363576109 464,460 6,859 1.50 21,969 2.69 0.1325
2015-05-14 2015-03-31 13F GALLAGHER ARTHUR J COM 363576109 457,601 2,948 0.65 21,393 -0.06 0.1334
2015-02-12 2014-12-31 13F GALLAGHER ARTHUR J COM 363576109 454,653 39,688 9.56 21,406 13.73 0.1340
2014-11-14 2014-09-30 13F GALLAGHER ARTHUR J COM 363576109 414,965 377,383 1,004.16 18,822 974.32 0.1319
2014-08-13 2014-06-30 13F GALLAGHER ARTHUR J. COMMON 363576109 37,582 5,711 17.92 1,752 15.57 0.0733
2014-05-14 2014-03-31 13F GALLAGHER ARTHUR J. COMMON STOCK 363576109 31,871 4,437 16.17 1,516 17.70 0.0629
2014-02-12 2013-12-31 13F GALLAGHER ARTHUR J. COMMON STOCK 363576109 27,434 -5,852 -17.58 1,288 -11.36 0.0540
2013-11-13 2013-09-30 13F GALLAGHER ARTHUR J. COMMON STOCK 363576109 33,286 4,843 17.03 1,453 16.99 0.0693
2013-07-30 2013-06-30 13F GALLAGHER ARTHUR J. COMMON STOCK 363576109 28,443 28,443 1,242 0.0602
Disclosed Call Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share
Price
Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2026-05-12 2026-03-31 13F GALLAGHER ARTHUR J COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2026-01-28 2025-12-31 13F GALLAGHER ARTHUR J COM Call 101 3 n/a n/a n/a
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.