Merck & Co., Inc.
MX ˙ BMV ˙ US58933Y1055
SecurityMX:MRK / Merck & Co., Inc.
InstitutionPuzo Michael J
Latest Disclosed Ownership17,553 shares
Latest Disclosed Value $ 2,111,450
Puzo Michael J ownership in MRK / Merck & Co., Inc.

On May 7, 2026 - Puzo Michael J filed a 13F-HR form disclosing ownership of 17,553 shares of Merck & Co., Inc. (MX:MRK) valued at $2,111,450 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 14, 2026 disclosing 17,553 shares of Merck & Co., Inc.. This represents a change in shares of 0.00% 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)
2026-05-07 2026-03-31 13F MERCK COM 58933Y105 17,553 0 0.00 2,111 14.29 0.6148
2026-02-14 2025-12-31 13F MERCK COM 58933Y105 17,553 0 0.00 1,848 25.39 0.5030
2025-11-10 2025-09-30 13F MERCK COM 58933Y105 17,553 -405 -2.26 1,473 3.66 0.4018
2025-07-23 2025-06-30 13F MERCK COM 58933Y105 17,958 0 0.00 1,422 -11.79 0.4050
2025-04-21 2025-03-31 13F MERCK COM 58933Y105 17,958 -245 -1.35 1,612 -10.99 0.4619
2025-02-13 2024-12-31 13F MERCK COM 58933Y105 18,203 -1,500 -7.61 1,811 -19.09 0.5062
2024-11-12 2024-09-30 13F MERCK COM 58933Y105 19,703 -1,102 -5.30 2,237 -13.13 0.5849
2024-08-12 2024-06-30 13F MERCK COM 58933Y105 20,805 -505 -2.37 2,576 -8.40 0.7149
2024-05-13 2024-03-31 13F MERCK COM 58933Y105 21,310 -940 -4.22 2,812 15.92 0.7794
2024-02-14 2023-12-31 13F MERCK COM 58933Y105 22,250 -85 -0.38 2,426 5.48 0.7705
2023-11-14 2023-09-30 13F MERCK COM 58933Y105 22,335 -540 -2.36 2,299 -12.88 0.7799
2023-08-11 2023-06-30 13F MERCK COM 58933Y105 22,875 -225 -0.97 2,640 7.41 0.8356
2023-05-11 2023-03-31 13F MERCK COM 58933Y105 23,100 -250 -1.07 2,458 -5.14 0.8199
2023-02-09 2022-12-31 13F MERCK COM 58933Y105 23,350 0 0.00 2,591 28.79 0.9355
2022-11-08 2022-09-30 13F MERCK COM 58933Y105 23,350 0 0.00 2,011 -5.54 0.7644
2022-07-19 2022-06-30 13F MERCK COM 58933Y105 23,350 -350 -1.48 2,129 9.46 0.7560
2022-05-17 2022-03-31 13F MERCK COM 58933Y105 23,700 -300 -1.25 1,945 5.76 0.5854
2022-02-08 2021-12-31 13F MERCK COM 58933Y105 24,000 0 0.00 1,839 2.00 0.5194
2021-11-10 2021-09-30 13F MERCK COM 58933Y105 24,000 0 0.00 1,803 -3.43 0.5715
2021-08-09 2021-06-30 13F MERCK COM 58933Y105 24,000 -100 -0.41 1,867 0.48 0.5801
2021-05-17 2021-03-31 13F MERCK COM 58933Y105 24,100 0 0.00 1,858 -5.73 0.5915
2021-02-16 2020-12-31 13F MERCK COM 58933Y105 24,100 0 0.00 1,971 -1.40 0.6435
2020-10-28 2020-09-30 13F MERCK COM 58933Y105 24,100 -100 -0.41 1,999 6.78 0.7114
2020-07-28 2020-06-30 13F MERCK COM 58933Y105 24,200 -300 -1.22 1,872 -0.79 0.7003
2020-05-07 2020-03-31 13F MERCK COM 58933Y105 24,500 500 2.08 1,887 -13.56 0.8304
2020-01-15 2019-12-31 13F MERCK COM 58933Y105 24,000 -732 -2.96 2,183 4.90 0.7812
2019-11-06 2019-09-30 13F MERCK COM 58933Y105 24,732 -800 -3.13 2,081 -2.80 0.7838
2019-07-24 2019-06-30 13F MERCK COM 58933Y105 25,532 -800 -3.04 2,141 -2.24 0.7952
2019-05-01 2019-03-31 13F MERCK COM 58933Y105 26,332 -2,400 -8.35 2,190 -0.32 0.8537
2019-01-24 2018-12-31 13F MERCK COM 58933Y105 28,732 -320 -1.10 2,197 6.55 0.9760
2018-10-15 2018-09-30 13F MERCK COM 58933Y105 29,052 -850 -2.84 2,062 13.67 0.7779
2018-07-30 2018-06-30 13F MERCK COM 58933Y105 29,902 -800 -2.61 1,814 8.43 0.7680
2018-04-24 2018-03-31 13F MERCK COM 58933Y105 30,702 -500 -1.60 1,673 -4.67 0.7126
2018-02-02 2017-12-31 13F MERCK COM 58933Y105 31,202 2,770 9.74 1,755 -3.62 0.7232
2017-10-26 2017-09-30 13F MERCK COM 58933Y105 28,432 -400 -1.39 1,821 -1.46 0.9476
2017-07-25 2017-06-30 13F MERCK COM 58933Y105 28,832 -461 -1.57 1,848 -0.70 0.9973
2017-05-16 2017-03-31 13F MERCK COM 58933Y105 29,293 -70 -0.24 1,861 7.63 1.0336
2017-02-14 2016-12-31 13F MERCK Common Stock 58933Y105 29,363 0 0.00 1,729 -5.62 1.0003
2016-11-16 2016-09-30 13F MERCK Common Stock 58933Y105 29,363 1,950 7.11 1,832 15.95 1.0564
2016-08-08 2016-06-30 13F MERCK Common Stock 58933Y105 27,413 0 0.00 1,580 8.89 1.0422
2016-05-27 2016-03-31 13F MERCK Common Stock 58933Y105 27,413 0 0.00 1,451 0.21 0.9626
2016-02-12 2015-12-31 13F MERCK Common Stock 58933Y105 27,413 -130 -0.47 1,448 6.47 1.0114
2015-11-13 2015-09-30 13F MERCK Common Stock 58933Y105 27,543 -430 -1.54 1,360 -14.57 0.9662
2015-08-10 2015-06-30 13F MERCK Common Stock 58933Y105 27,973 0 0.00 1,592 -0.93 1.0258
2015-05-22 2015-03-31 13F MERCK Common Stock 58933Y105 27,973 0 0.00 1,607 1.13 1.0264
2015-02-13 2014-12-31 13F MERCK Common Stock 58933Y105 27,973 310 1.12 1,589 -3.05 1.0429
2014-11-24 2014-09-30 13F MERCK Common Stock 58933Y105 27,663 -839 -2.94 1,639 -0.61 1.1246
2014-07-24 2014-06-30 13F MERCK Common Stock 58933Y105 28,502 0 0.00 1,649 1.92 1.1440
2014-05-30 2014-03-31 13F MERCK Common Stock 58933Y105 28,502 0 0.00 1,618 13.46 1.1647
2014-05-28 2013-12-31 13F MERCK Common Stock 58933Y105 28,502 0 0.00 1,426 5.08 1.0401
2013-11-18 2013-09-30 13F MERCK Common Stock 58933Y105 28,502 0 0.00 1,357 2.57 1.1346
2013-08-19 2013-06-30 13F MERCK Common Stock 58933Y105 28,502 0 0.00 1,323 5.08 1.1614
2013-08-16 2013-03-31 13F MERCK Common Stock 58933Y105 28,502 0 0.00 1,259 7.88 1.0974
2013-08-16 2012-12-31 13F MERCK Common Stock 58933Y105 28,502 28,502 1,167 1.1135
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.