Merck & Co., Inc.
CH ˙ SWX ˙ US58933Y1055
SecurityCH:MRK / Merck & Co., Inc.
InstitutionRe Advisers Corp
Latest Disclosed Ownership210,577 shares
Latest Disclosed Value $ 25,270,794
Re Advisers Corp reports 0.99% decrease in ownership of MRK / Merck & Co., Inc.

On May 8, 2026 - Re Advisers Corp filed a 13F-HR form disclosing ownership of 210,577 shares of Merck & Co., Inc. (CH:MRK) valued at $25,270,794 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 10, 2026 disclosing 212,677 shares of Merck & Co., Inc.. This represents a change in shares of -0.99% 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)
2026-05-08 2026-03-31 13F MERCK COM 58933Y105 210,577 -2,100 -0.99 25,271 12.88 0.6788
2026-02-10 2025-12-31 13F MERCK COM 58933Y105 212,677 -26,427 -11.05 22,386 11.56 0.5928
2025-11-05 2025-09-30 13F MERCK COM 58933Y105 239,104 -399,300 -62.55 20,068 -60.29 0.4780
2025-08-05 2025-06-30 13F MERCK COM 58933Y105 638,404 -40,400 -5.95 50,536 -17.06 1.1975
2025-05-06 2025-03-31 13F MERCK COM 58933Y105 678,804 0 0.00 60,929 -9.77 1.4918
2025-02-12 2024-12-31 13F MERCK COM 58933Y105 678,804 24,800 3.79 67,527 -9.08 1.6288
2024-11-01 2024-09-30 13F MERCK COM 58933Y105 654,004 -500 -0.08 74,269 -8.34 1.7673
2024-07-23 2024-06-30 13F MERCK COM 58933Y105 654,504 -11,200 -1.68 81,028 -7.73 1.9969
2024-05-10 2024-03-31 13F MERCK COM 58933Y105 665,704 -1,000 -0.15 87,818 20.82 2.0597
2024-02-13 2023-12-31 13F MERCK COM 58933Y105 666,704 1,100 0.17 72,684 6.07 1.8573
2023-11-09 2023-09-30 13F MERCK COM 58933Y105 665,604 10,000 1.53 68,524 -9.42 1.9028
2023-07-25 2023-06-30 13F MERCK COM 58933Y105 655,604 3,200 0.49 75,650 8.99 2.0060
2023-04-27 2023-03-31 13F MERCK COM 58933Y105 652,404 -13,700 -2.06 69,409 -6.06 1.9346
2023-02-03 2022-12-31 13F MERCK COM 58933Y105 666,104 -2,500 -0.37 73,888 28.32 1.9713
2022-11-07 2022-09-30 13F MERCK COM 58933Y105 668,604 -1,500 -0.22 57,580 -5.75 1.7421
2022-08-01 2022-06-30 13F MERCK COM 58933Y105 670,104 0 0.00 61,093 11.11 1.7280
2022-05-12 2022-03-31 13F MERCK COM 58933Y105 670,104 -10,200 -1.50 54,982 5.45 1.3460
2022-02-07 2021-12-31 13F MERCK COM 58933Y105 680,304 -4,900 -0.72 52,138 1.31 1.1997
2021-11-05 2021-09-30 13F MERCK COM 58933Y105 685,204 2,700 0.40 51,466 -3.04 1.2517
2021-08-02 2021-06-30 13F MERCK COM 58933Y105 682,504 -75,300 -9.94 53,078 -9.14 1.2262
2021-05-07 2021-03-31 13F MERCK & CO. COM 58933Y105 757,804 -182,400 -19.40 58,419 -24.04 1.3966
2021-02-10 2020-12-31 13F MERCK & CO. COM 58933Y105 940,204 -22,300 -2.32 76,909 -3.67 1.9016
2020-11-13 2020-09-30 13F MERCK & CO. COM 58933Y105 962,504 -333,100 -25.71 79,840 -20.31 2.1864
2020-08-13 2020-06-30 13F MERCK & CO. COM 58933Y105 1,295,604 700 0.05 100,189 0.56 2.5736
2020-05-14 2020-03-31 13F MERCK COM 58933Y105 1,294,904 -48,240 -3.59 99,630 -18.44 2.9363
2020-02-13 2019-12-31 13F MERCK COM 58933Y105 1,343,144 -13,699 -1.01 122,159 6.95 2.5449
2019-11-14 2019-09-30 13F MERCK COM 58933Y105 1,356,843 -47,378 -3.37 114,219 -2.99 2.3037
2019-08-12 2019-06-30 13F MERCK COM 58933Y105 1,404,221 -397,279 -22.05 117,744 -21.42 2.2293
2019-05-14 2019-03-31 13F MERCK COM 58933Y105 1,801,500 -70,000 -3.74 149,831 4.78 2.8010
2019-02-13 2018-12-31 13F MERCK COM 58933Y105 1,871,500 0 0.00 143,001 7.71 2.7763
2018-11-13 2018-09-30 13F MERCK COM 58933Y105 1,871,500 0 0.00 132,764 16.87 2.0316
2018-08-10 2018-06-30 13F MERCK COM 58933Y105 1,871,500 0 0.00 113,600 11.44 1.7849
2018-05-11 2018-03-31 13F MERCK COM 58933Y105 1,871,500 0 0.00 101,941 -3.20 1.5308
2018-02-13 2017-12-31 13F MERCK COM 58933Y105 1,871,500 0 0.00 105,309 -12.12 1.5066
2017-11-13 2017-09-30 13F MERCK COM 58933Y105 1,871,500 0 0.00 119,832 -0.09 1.8233
2017-07-21 2017-06-30 13F MERCK COM 58933Y105 1,871,500 0 0.00 119,944 0.87 1.8759
2017-05-11 2017-03-31 13F MERCK COM 58933Y105 1,871,500 0 0.00 118,915 7.93 1.8973
2017-02-14 2016-12-31 13F MERCK COM 58933Y105 1,871,500 477,520 34.26 110,175 26.64 1.7342
2016-11-14 2016-09-30 13F MERCK + COM 58933Y105 1,393,980 505,000 56.81 86,998 69.87 1.4413
2016-08-10 2016-06-30 13F MERCK + COM 58933Y105 888,980 0 0.00 51,214 8.88 0.8796
2016-05-13 2016-03-31 13F MERCK + COM 58933Y105 888,980 888,980 47,036 0.8413
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.