Merck & Co., Inc.
MX ˙ BMV ˙ US58933Y1055
SecurityMX:MRK / Merck & Co., Inc.
InstitutionWright Investors Service Inc
Latest Disclosed Ownership27,928 shares
Latest Disclosed Value $ 3,359,459
Wright Investors Service Inc reports 663.89% increase in ownership of MRK / Merck & Co., Inc.

On April 29, 2026 - Wright Investors Service Inc filed a 13F-HR form disclosing ownership of 27,928 shares of Merck & Co., Inc. (MX:MRK) valued at $3,359,459 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 26, 2026 disclosing 3,656 shares of Merck & Co., Inc.. This represents a change in shares of 663.89% 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)
2026-04-29 2026-03-31 13F MERCK COM 58933Y105 27,928 24,272 663.89 3,359 774.74 1.0574
2026-01-26 2025-12-31 13F MERCK COM 58933Y105 3,656 -115 -3.05 385 21.52 0.1155
2025-10-28 2025-09-30 13F MERCK COM 58933Y105 3,771 -10,466 -73.51 316 -71.96 0.0916
2025-07-11 2025-06-30 13F MERCK COM 58933Y105 14,237 4,348 43.97 1,127 27.06 0.3402
2025-04-09 2025-03-31 13F MERCK COM 58933Y105 9,889 -1,814 -15.50 888 -23.80 0.2934
2025-01-13 2024-12-31 13F MERCK COM 58933Y105 11,703 -9,695 -45.31 1,164 -52.08 0.3781
2024-10-04 2024-09-30 13F MERCK COM 58933Y105 21,398 -7,082 -24.87 2,430 -31.09 0.6360
2024-07-26 2024-06-30 13F MERCK COM 58933Y105 28,480 -10,542 -27.02 3,526 -31.53 0.9286
2024-05-02 2024-03-31 13F MERCK COM 58933Y105 39,022 1,120 2.95 5,149 24.59 1.3051
2024-01-31 2023-12-31 13F MERCK COM 58933Y105 37,902 -6,064 -13.79 4,132 -8.71 1.1639
2023-10-31 2023-09-30 13F MERCK COM 58933Y105 43,966 487 1.12 4,526 -9.79 1.3127
2023-07-27 2023-06-30 13F MERCK COM 58933Y105 43,479 2,943 7.26 5,017 16.35 1.4143
2023-04-26 2023-03-31 13F MERCK COM 58933Y105 40,536 1,552 3.98 4,313 -0.30 1.2258
2023-01-27 2022-12-31 13F MERCK COM 58933Y105 38,984 2,825 7.81 4,325 38.89 1.2399
2022-11-01 2022-09-30 13F MERCK COM 58933Y105 36,159 3,882 12.03 3,114 5.81 0.9787
2022-08-02 2022-06-30 13F MERCK COM 58933Y105 32,277 12,023 59.36 2,943 77.08 0.8408
2022-04-22 2022-03-31 13F MERCK COM 58933Y105 20,254 2,796 16.02 1,662 24.22 0.4130
2022-01-27 2021-12-31 13F MERCK COM 58933Y105 17,458 1,030 6.27 1,338 8.43 0.3384
2021-11-01 2021-09-30 13F MERCK COM 58933Y105 16,428 -10,808 -39.68 1,234 -41.74 0.3507
2021-08-03 2021-06-30 13F MERCK COM 58933Y105 27,236 824 3.12 2,118 4.03 0.5746
2021-04-29 2021-03-31 13F MERCK & CO. COM 58933Y105 26,412 2,365 9.83 2,036 3.51 0.6166
2021-02-02 2020-12-31 13F MERCK & CO. COM 58933Y105 24,047 506 2.15 1,967 0.72 0.6753
2020-11-06 2020-09-30 13F MERCK & CO. COM 58933Y105 23,541 23,541 1,953 0.6949
2016-04-25 2016-03-31 13F MERCK & CO INC COM 58933Y105 0 -16,501 -100.00 0 -100.00
2016-01-27 2015-12-31 13F MERCK & CO INC COM 58933Y105 16,501 8,740 112.61 872 127.68 0.3219
2015-10-27 2015-09-30 13F MERCK & CO INC COM 58933Y105 7,761 2,635 51.40 383 31.16 0.1731
2015-07-28 2015-06-30 13F MERCK & CO INC COM 58933Y105 5,126 5,126 292 0.1393
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.