Merck & Co., Inc.
MX ˙ BMV ˙ US58933Y1055
SecurityMX:MRK / Merck & Co., Inc.
InstitutionWinthrop Advisory Group LLC
Latest Disclosed Ownership7,451 shares
Latest Disclosed Value $ 902,635
Winthrop Advisory Group LLC reports 12.10% decrease in ownership of MRK / Merck & Co., Inc.

On April 13, 2026 - Winthrop Advisory Group LLC filed a 13F-HR form disclosing ownership of 7,451 shares of Merck & Co., Inc. (MX:MRK) valued at $902,635 USD as of March 31, 2026. The entity filed a previous 13F-HR/A on January 21, 2026 disclosing 8,477 shares of Merck & Co., Inc.. This represents a change in shares of -12.10% 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)
2026-04-13 2026-03-31 13F MERCK COM 58933Y105 7,451 -1,026 -12.10 903 0.22 0.0738
2026-01-21 2025-12-31 13F/A-1 MERCK COM 58933Y105 8,477 -48 -0.56 901 24.65 0.0763
2026-01-21 2025-12-31 13F MERCK COM 58933Y105 8,477 -48 901 0.0763
2025-10-24 2025-09-30 13F MERCK COM 58933Y105 8,525 -227 -2.59 722 3.29 0.0632
2025-07-23 2025-06-30 13F MERCK COM 58933Y105 8,752 453 5.46 700 -6.92 0.0675
2025-04-08 2025-03-31 13F MERCK COM 58933Y105 8,299 -633 -7.09 752 -15.43 0.0904
2025-01-13 2024-12-31 13F MERCK COM 58933Y105 8,932 522 6.21 889 -7.60 0.1066
2024-10-31 2024-09-30 13F MERCK COM 58933Y105 8,410 -172 -2.00 961 -9.51 0.1188
2024-07-18 2024-06-30 13F/A-1 MERCK COM 58933Y105 8,582 850 10.99 1,063 3.51 0.1444
2024-07-18 2024-06-30 13F MERCK COM 58933Y105 8,582 850 1,063 0.1444
2024-04-17 2024-03-31 13F MERCK COM 58933Y105 7,732 -913 -10.56 1,026 8.92 0.1485
2024-01-10 2023-12-31 13F MERCK COM 58933Y105 8,645 -283 -3.17 943 1.84 0.1472
2023-11-03 2023-09-30 13F MERCK COM 58933Y105 8,928 -1,066 -10.67 926 -20.26 0.1520
2023-08-02 2023-06-30 13F MERCK COM 58933Y105 9,994 66 0.66 1,160 9.02 0.1861
2023-08-01 2023-03-31 13F/A-1 MERCK COM 58933Y105 9,928 -776 -7.25 1,064 -10.96 0.1878
2023-04-17 2023-03-31 13F MERCK COM 58933Y105 9,928 -776 1 0.1879
2023-08-03 2022-12-31 13F/A-1 MERCK COM 58933Y105 10,704 2,689 33.55 1,195 71.70 0.2267
2023-01-18 2022-12-31 13F MERCK COM 58933Y105 10,704 2,689 1 0.0002
2022-11-04 2022-09-30 13F MERCK COM 58933Y105 8,015 -42 -0.52 696 -5.95 0.1490
2022-07-21 2022-06-30 13F MERCK COM 58933Y105 8,057 778 10.69 740 22.92 0.1737
2022-04-13 2022-03-31 13F MERCK COM 58933Y105 7,279 894 14.00 602 21.86 0.1255
2022-01-12 2021-12-31 13F MERCK COM 58933Y105 6,385 333 5.50 494 7.86 0.0992
2021-10-14 2021-09-30 13F MERCK COM 58933Y105 6,052 226 3.88 458 1.10 0.1020
2021-07-14 2021-06-30 13F MERCK COM 58933Y105 5,826 -854 -12.78 453 -12.04 0.1019
2021-04-23 2021-03-31 13F MERCK COM 58933Y105 6,680 -150 -2.20 515 -7.87 0.1270
2021-01-25 2020-12-31 13F MERCK COM 58933Y105 6,830 624 10.05 559 8.75 0.1462
2020-10-20 2020-09-30 13F MERCK COM 58933Y105 6,206 75 1.22 514 7.31 0.1575
2020-07-17 2020-06-30 13F MERCK COM 58933Y105 6,131 707 13.03 479 14.87 0.1691
2020-04-17 2020-03-31 13F MERCK & CO. COM 58933Y105 5,424 7 0.13 417 -15.42 0.1667
2020-01-06 2019-12-31 13F MERCK COM 58933Y105 5,417 -230 -4.07 493 3.79 0.1776
2019-10-10 2019-09-30 13F MERCK COM 58933Y105 5,647 721 14.64 475 15.01 0.1880
2019-07-17 2019-06-30 13F MERCK COM 58933Y105 4,926 962 24.27 413 24.77 0.1728
2019-04-23 2019-03-31 13F MERCK COM 58933Y105 3,964 461 13.16 331 23.51 0.1456
2019-01-15 2018-12-31 13F MERCK COM 58933Y105 3,503 -113 -3.12 268 4.28 0.1362
2018-10-29 2018-09-30 13F MERCK COM 58933Y105 3,616 3,616 257 0.1447
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.