Merck & Co., Inc.
MX ˙ BMV ˙ US58933Y1055
SecurityMX:MRK / Merck & Co., Inc.
InstitutionGardner Russo & Quinn Llc
Latest Disclosed Ownership2,141 shares
Latest Disclosed Value $ 257,536
Gardner Russo & Quinn Llc ownership in MRK / Merck & Co., Inc.

On May 13, 2026 - Gardner Russo & Quinn Llc filed a 13F-HR form disclosing ownership of 2,141 shares of Merck & Co., Inc. (MX:MRK) valued at $257,536 USD as of March 31, 2026. The entity filed a previous 13F-HR on August 13, 2025 disclosing 0 shares of Merck & Co., Inc..

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)
2026-05-13 2026-03-31 13F Merck COM 58933Y105 2,141 2,141 258 0.0030
2025-08-13 2025-06-30 13F Merck COM 58933Y105 0 -2,763 -100.00 0 -100.00
2025-05-13 2025-03-31 13F Merck COM 58933Y105 2,763 -163 -5.57 248 -14.78 0.0028
2025-02-12 2024-12-31 13F Merck COM 58933Y105 2,926 -161 -5.22 291 -16.86 0.0033
2024-11-13 2024-09-30 13F Merck COM 58933Y105 3,087 -359 -10.42 351 -17.84 0.0036
2024-08-13 2024-06-30 13F Merck COM 58933Y105 3,446 -67 -1.91 427 -7.99 0.0045
2024-05-14 2024-03-31 13F Merck COM 58933Y105 3,513 -293 -7.70 464 11.84 0.0048
2024-02-13 2023-12-31 13F Merck COM 58933Y105 3,806 -36 -0.94 415 4.81 0.0042
2023-11-14 2023-09-30 13F Merck COM 58933Y105 3,842 -118 -2.98 396 -13.38 0.0043
2023-08-11 2023-06-30 13F Merck COM 58933Y105 3,960 129 3.37 457 12.04 0.0045
2023-05-11 2023-03-31 13F Merck COM 58933Y105 3,831 158 4.30 408 0.00 0.0042
2023-02-13 2022-12-31 13F Merck COM 58933Y105 3,673 -185 -4.80 408 22.59 0.0045
2022-11-10 2022-09-30 13F Merck COM 58933Y105 3,858 -51 -1.30 332 -6.74 0.0040
2022-08-04 2022-06-30 13F Merck COM 58933Y105 3,909 10 0.26 356 11.25 0.0040
2022-05-12 2022-03-31 13F Merck COM 58933Y105 3,899 11 0.28 320 7.38 0.0031
2022-02-10 2021-12-31 13F Merck COM 58933Y105 3,888 10 0.26 298 2.41 0.0027
2021-11-15 2021-09-30 13F Merck COM 58933Y105 3,878 10 0.26 291 -3.32 0.0027
2021-08-12 2021-06-30 13F Merck COM 58933Y105 3,868 10 0.26 301 1.35 0.0025
2021-05-12 2021-03-31 13F Merck COM 58933Y105 3,858 -86 -2.18 297 -8.05 0.0027
2021-02-11 2020-12-31 13F Merck COM 58933Y105 3,944 9 0.23 323 -0.92 0.0029
2020-11-12 2020-09-30 13F Merck COM 58933Y105 3,935 9 0.23 326 7.24 0.0032
2020-08-14 2020-06-30 13F Merck COM 58933Y105 3,926 1,175 42.71 304 43.40 0.0031
2020-05-13 2020-03-31 13F Merck COM 58933Y105 2,751 0 0.00 212 -15.20 0.0021
2020-02-11 2019-12-31 13F Merck COM 58933Y105 2,751 -30 -1.08 250 6.84 0.0019
2019-11-13 2019-09-30 13F Merck COM 58933Y105 2,781 0 0.00 234 0.43 0.0018
2019-08-13 2019-06-30 13F Merck COM 58933Y105 2,781 -5 -0.18 233 0.43 0.0018
2019-05-15 2019-03-31 13F Merck COM 58933Y105 2,786 0 0.00 232 8.92 0.0018
2019-02-13 2018-12-31 13F Merck COM 58933Y105 2,786 2,786 213 0.0018
2018-05-11 2018-03-31 13F Merck COM 58933Y105 0 -2,886 -100.00 0 -100.00
2018-02-14 2017-12-31 13F Merck COM 58933Y105 2,886 2,886 162 0.0011
2016-08-12 2016-06-30 13F Merck COM 58933Y105 0 -3,836 -100.00 0 -100.00
2016-05-12 2016-03-31 13F Merck COM 58933Y105 3,836 0 0.00 203 0.00 0.0017
2016-02-11 2015-12-31 13F Merck COM 58933Y105 3,836 3,836 0.00 203 0.0017
2015-11-12 2015-09-30 13F Merck COM 58933Y105 0 -3,836 -100.00 0 -100.00
2015-08-11 2015-06-30 13F Merck COM 58933Y105 3,836 0 0.00 218 -0.91 0.0019
2015-05-14 2015-03-31 13F Merck COM 58933Y105 3,836 -500 -11.53 220 -10.57 0.0020
2015-02-12 2014-12-31 13F Merck COM 58933Y105 4,336 0 0.00 246 -4.28 0.0022
2014-11-13 2014-09-30 13F Merck COM 58933Y105 4,336 -50 -1.14 257 1.18 0.0024
2014-08-13 2014-06-30 13F Merck COM 58933Y105 4,386 -150 -3.31 254 -1.55 0.0023
2014-05-13 2014-03-31 13F Merck COM 58933Y105 4,536 0 0.00 258 13.66 0.0025
2014-02-12 2013-12-31 13F Merck COM 58933Y105 4,536 -1,200 -20.92 227 -16.85 0.0022
2013-11-14 2013-09-30 13F Merck COM 58933Y105 5,736 0 0.00 273 2.63 0.0029
2013-08-13 2013-06-30 13F Merck COM 58933Y105 5,736 5,736 266 0.0031
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.