Merck & Co., Inc.
MX ˙ BMV ˙ US58933Y1055
SecurityMX:MRK / Merck & Co., Inc.
InstitutionGWM Advisors LLC
Latest Disclosed Ownership341,876 shares
Latest Disclosed Value $ 8,965,184
GWM Advisors LLC reports 13.76% decrease in ownership of MRK / Merck & Co., Inc.

On May 15, 2026 - GWM Advisors LLC filed a 13F-HR form disclosing ownership of 341,876 shares of Merck & Co., Inc. (MX:MRK) valued at $8,965,184 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 18, 2026 disclosing 396,431 shares of Merck & Co., Inc.. This represents a change in shares of -13.76% 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)
2026-05-15 2026-03-31 13F MERCK COM 58933Y105 341,876 -54,555 -13.76 8,965 -78.52 0.4151
2026-02-18 2025-12-31 13F MERCK COM 58933Y105 396,431 55,273 16.20 41,728 45.73 0.1514
2025-11-17 2025-09-30 13F MERCK Common Stock 58933Y105 341,158 -25,231 -6.89 28,633 -1.28 0.1302
2025-08-14 2025-06-30 13F MERCK COM 58933Y105 366,389 -39,977 -9.84 29,003 -20.49 0.1495
2025-05-15 2025-03-31 13F MERCK Common Stock 58933Y105 406,366 -4,357 -1.06 36,475 -10.73 0.2167
2025-02-13 2024-12-31 13F MERCK COM 58933Y105 410,723 16,837 4.27 40,859 -8.65 0.2455
2024-11-14 2024-09-30 13F MERCK COM 58933Y105 393,886 -261,688 -39.92 44,730 -44.89 0.2901
2024-08-16 2024-06-30 13F MERCK COM 58933Y105 655,574 45,591 7.47 81,160 0.83 0.5909
2024-05-14 2024-03-31 13F MERCK COM 58933Y105 609,983 19,644 3.33 80,487 21.71 0.7020
2024-02-13 2023-12-31 13F MERCK COM 58933Y105 590,339 39,515 7.17 66,132 16.62 0.6278
2023-11-14 2023-09-30 13F MERCK COM 58933Y105 550,824 22,909 4.34 56,708 -6.91 0.6231
2023-08-14 2023-06-30 13F MERCK COM 58933Y105 527,915 -7,449 -1.39 60,916 5.95 0.6883
2023-05-12 2023-03-31 13F MERCK Common Stock 58933Y105 535,364 8,483 1.61 57,495 221.52 0.7188
2023-02-14 2022-12-31 13F MERCK COM 58933Y105 526,881 45,732 9.50 17,883 -56.85 0.4825
2022-11-14 2022-09-30 13F MERCK COM 58933Y105 481,149 283,559 143.51 41,437 130.03 0.6809
2022-08-09 2022-06-30 13F MERCK COM 58933Y105 197,590 38,365 24.09 18,014 37.89 0.2984
2022-05-13 2022-03-31 13F MERCK COM 58933Y105 159,225 9,376 6.26 13,064 13.76 0.2101
2022-02-17 2021-12-31 13F MERCK COM 58933Y105 149,849 75,361 101.17 11,484 105.25 0.1732
2021-10-29 2021-09-30 13F MERCK Common Stock 58933Y105 74,488 -21,412 -22.33 5,595 -24.98 0.1384
2021-07-22 2021-06-30 13F MERCK Common Stock 58933Y105 95,900 5,999 6.67 7,458 7.62 0.1984
2021-04-26 2021-03-31 13F MERCK Common Stock 58933Y105 89,901 -38,367 -29.91 6,930 -33.95 0.2064
2021-01-27 2020-12-31 13F MERCK Common Stock 58933Y105 128,268 -212,392 -62.35 10,492 -62.87 0.3439
2020-11-03 2020-09-30 13F MERCK Common Stock 58933Y105 340,660 27,801 8.89 28,258 16.80 0.9823
2020-07-29 2020-06-30 13F MERCK & CO. Common Stock 58933Y105 312,859 14,517 4.87 24,193 5.40 0.9454
2020-05-04 2020-03-31 13F MERCK COM 58933Y105 298,342 -1,037 -0.35 22,954 -15.70 1.1057
2020-01-31 2019-12-31 13F MERCK Common Stock 58933Y105 299,379 28,530 10.53 27,228 19.23 1.0831
2019-11-06 2019-09-30 13F MERCK COM 58933Y105 270,849 84,600 45.42 22,836 46.23 1.0145
2019-08-05 2019-06-30 13F MERCK COM 58933Y105 186,249 21,621 13.13 15,617 14.06 0.9562
2019-05-14 2019-03-31 13F/A-1 MERCK COM 58933Y105 164,628 122,027 286.44 13,692 320.65 0.8843
2019-05-09 2019-03-31 13F MERCK COM 58933Y105 13,819 -28,782 17
2019-01-28 2018-12-31 13F MERCK COM 58933Y105 42,601 1,565 3.81 3,255 11.82 0.2098
2018-10-29 2018-09-30 13F MERCK COM 58933Y105 41,036 3,098 8.17 2,911 26.90 0.2236
2018-07-19 2018-06-30 13F MERCK COM 58933Y105 37,938 6,390 20.25 2,294 36.47 0.2096
2018-05-11 2018-03-31 13F MERCK COM 58933Y105 31,548 3,958 14.35 1,681 7.55 0.1920
2018-02-08 2017-12-31 13F MERCK COM 58933Y105 27,590 41 0.15 1,563 -11.79 0.2114
2017-11-13 2017-09-30 13F MERCK Common Stock 58933Y105 27,549 -547 -1.95 1,772 0.40 0.2752
2017-08-17 2017-06-30 13F/A-1 MERCK Common Stock 58933Y105 28,096 7,747 38.07 1,765 36.40 0.3033
2017-08-16 2017-06-30 13F AMERICAN TOWER Common Stock 58933Y105 28,096 7,747 1,765
2017-05-09 2017-03-31 13F MERCK COM 58933Y105 20,349 -6,513 -24.25 1,294 -21.77 0.2941
2017-02-02 2016-12-31 13F MERCK COM 58933Y105 26,862 15,879 144.58 1,654 140.76 0.4587
2017-01-18 2016-09-30 13F/A-1 MERCK COM 58933Y105 10,983 4,676 74.14 687 89.26 0.2167
2016-10-20 2016-09-30 13F MERCK COM 58933Y105 11,198 700
2016-07-14 2016-06-30 13F MERCK COM 58933Y105 6,307 6,307 363 0.1502
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.