Merck & Co., Inc.
MX ˙ BMV ˙ US58933Y1055
SecurityMX:MRK / Merck & Co., Inc.
InstitutionWelch & Forbes Llc
Latest Disclosed Ownership317,368 shares
Latest Disclosed Value $ 38,176,176
Welch & Forbes Llc reports 1.51% decrease in ownership of MRK / Merck & Co., Inc.

On May 1, 2026 - Welch & Forbes Llc filed a 13F-HR form disclosing ownership of 317,368 shares of Merck & Co., Inc. (MX:MRK) valued at $38,176,176 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 10, 2026 disclosing 322,229 shares of Merck & Co., Inc.. This represents a change in shares of -1.51% 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)
2026-05-01 2026-03-31 13F MERCK COM 58933Y105 317,368 -4,861 -1.51 38,176 12.56 0.4936
2026-02-10 2025-12-31 13F MERCK COM 58933Y105 322,229 -4,524 -1.38 33,918 23.68 0.4109
2025-11-04 2025-09-30 13F MERCK COM 58933Y105 326,753 -4,855 -1.46 27,424 4.47 0.3303
2025-08-05 2025-06-30 13F MERCK COM 58933Y105 331,608 -5,950 -1.76 26,250 -13.36 0.3278
2025-05-02 2025-03-31 13F MERCK COM 58933Y105 337,558 -22,924 -6.36 30,299 -15.51 0.3964
2025-02-07 2024-12-31 13F MERCK COM 58933Y105 360,482 -7,083 -1.93 35,861 -14.09 0.4610
2024-11-04 2024-09-30 13F MERCK COM 58933Y105 367,565 -4,446 -1.20 41,741 -10.87 0.5312
2024-08-02 2024-06-30 13F MERCK COM 58933Y105 372,011 -1,621 -0.43 46,833 -5.01 0.6250
2024-05-03 2024-03-31 13F MERCK COM 58933Y105 373,632 -7,214 -1.89 49,301 18.74 0.6768
2024-02-06 2023-12-31 13F MERCK COM 58933Y105 380,846 -12,375 -3.15 41,520 2.56 0.6272
2023-11-03 2023-09-30 13F MERCK COM 58933Y105 393,221 -4,653 -1.17 40,482 -11.82 0.6693
2023-07-28 2023-06-30 13F MERCK COM 58933Y105 397,874 -2,804 -0.70 45,911 7.70 0.7242
2023-04-14 2023-03-31 13F MERCK COM 58933Y105 400,678 -4,064 -1.00 42,628 -5.07 0.7219
2023-02-02 2022-12-31 13F MERCK COM 58933Y105 404,742 -377 -0.09 44,906 28.71 0.8049
2022-10-31 2022-09-30 13F MERCK COM 58933Y105 405,119 2,848 0.71 34,890 -4.87 0.6814
2022-07-22 2022-06-30 13F MERCK COM 58933Y105 402,271 -613 -0.15 36,675 10.95 0.6710
2022-04-25 2022-03-31 13F MERCK COM 58933Y105 402,884 1,440 0.36 33,056 7.44 0.5208
2022-01-19 2021-12-31 13F MERCK COM 58933Y105 401,444 -5,386 -1.32 30,767 0.69 0.4606
2021-10-13 2021-09-30 13F MERCK COM 58933Y105 406,830 -10,091 -2.42 30,557 -5.76 0.5078
2021-07-22 2021-06-30 13F MERCK COM 58933Y105 416,921 -10,702 -2.50 32,425 -1.64 0.5479
2021-04-14 2021-03-31 13F MERCK & CO. COM 58933Y105 427,623 -3,435 -0.80 32,965 -6.51 0.6088
2021-01-20 2020-12-31 13F MERCK & CO. COM 58933Y105 431,058 -7,520 -1.71 35,261 -3.08 0.6898
2020-10-23 2020-09-30 13F MERCK & CO. COM 58933Y105 438,578 -3,306 -0.75 36,380 6.46 0.7851
2020-07-15 2020-06-30 13F MERCK & CO. COM 58933Y105 441,884 -12,297 -2.71 34,172 -2.21 0.8004
2020-04-17 2020-03-31 13F MERCK & CO. COM 58933Y105 454,181 1,818 0.40 34,944 -15.06 0.9760
2020-01-17 2019-12-31 13F MERCK COM 58933Y105 452,363 1,489 0.33 41,142 8.40 0.9154
2019-10-11 2019-09-30 13F MERCK COM 58933Y105 450,874 -2,692 -0.59 37,954 -0.20 0.9058
2019-07-12 2019-06-30 13F MERCK COM 58933Y105 453,566 -6,190 -1.35 38,031 -0.54 0.9258
2019-04-29 2019-03-31 13F MERCK COM 58933Y105 459,756 -19,275 -4.02 38,238 4.47 0.9593
2019-02-05 2018-12-31 13F MERCK COM 58933Y105 479,031 -11,954 -2.43 36,603 5.09 1.0319
2018-10-17 2018-09-30 13F MERCK COM 58933Y105 490,985 -6,727 -1.35 34,831 15.29 0.8302
2018-07-16 2018-06-30 13F MERCK COM 58933Y105 497,712 -10,842 -2.13 30,211 9.06 0.7811
2018-04-12 2018-03-31 13F MERCK COM 58933Y105 508,554 1,702 0.34 27,701 -2.87 0.7138
2018-01-26 2017-12-31 13F MERCK COM 58933Y105 506,852 -29,081 -5.43 28,520 -16.89 0.7612
2017-11-13 2017-09-30 13F MERCK COM 58933Y105 535,933 -6,795 -1.25 34,316 -1.34 0.9033
2017-07-31 2017-06-30 13F MERCK COM 58933Y105 542,728 -7,664 -1.39 34,783 -0.54 0.9721
2017-07-31 2017-03-31 13F/A-1 MERCK COM 58933Y105 550,392 2,996 0.55 34,971 8.52 1.0009
2017-04-27 2017-03-31 13F MERCK COM 58933Y105 547,259 34,772
2017-02-07 2016-12-31 13F MERCK COM 58933Y105 547,396 -1,771 -0.32 32,226 -5.98 0.9643
2016-11-02 2016-09-30 13F MERCK COM 58933Y105 549,167 -2,953 -0.53 34,274 7.75 1.1852
2016-08-02 2016-06-30 13F MERCK COM 58933Y105 552,120 -2,650 -0.48 31,808 8.36 0.9693
2016-05-05 2016-03-31 13F MERCK & CO INC COM 58933Y105 554,770 -180 -0.03 29,353 0.14 0.9141
2016-01-27 2015-12-31 13F MERCK & CO INC COM 58933Y105 554,950 7,589 1.39 29,312 8.43 0.9405
2015-11-05 2015-09-30 13F MERCK & CO INC COM 58933Y105 547,361 7,389 1.37 27,034 -12.06 0.9024
2015-08-11 2015-06-30 13F MERCK & CO INC COM 58933Y105 539,972 -7,736 -1.41 30,741 -2.35 0.9564
2015-04-30 2015-03-31 13F MERCK & CO INC COM 58933Y105 547,708 547,708 0.00 31,482 0.9459
2015-01-27 2014-12-31 13F MERCK & CO INC COM 58933Y105 0 -614,934 -100.00 0 -100.00
2014-10-27 2014-09-30 13F MERCK & CO INC COM 58933Y105 614,934 -574 -0.09 36,453 2.37 1.1128
2014-07-31 2014-06-30 13F MERCK & CO INC COM 58933Y105 615,508 -1,382 -0.22 35,608 1.68 1.1239
2014-05-01 2014-03-31 13F MERCK & CO INC COM 58933Y105 616,890 -1,771 -0.29 35,021 13.10 1.1093
2014-01-17 2013-12-31 13F MERCK & CO INC COM 58933Y105 618,661 -10,674 -1.70 30,964 3.34 0.9803
2013-10-31 2013-09-30 13F MERCK & CO INC COM 58933Y105 629,335 -810 -0.13 29,962 2.36 1.0086
2013-08-08 2013-06-30 13F MERCK & CO INC COM 58933Y105 630,145 630,145 29,270 1.0465
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.