Merck & Co., Inc.
CL ˙ SNSE ˙ US58933Y1055
SecurityCL:MRKCL / Merck & Co., Inc.
InstitutionFirst Manhattan Co
Latest Disclosed Ownership154,467 shares
Latest Disclosed Value $ 18,711,471
First Manhattan Co reports 1.35% decrease in ownership of MRKCL / Merck & Co., Inc.

On May 15, 2026 - First Manhattan Co filed a 13F-HR form disclosing ownership of 154,467 shares of Merck & Co., Inc. (CL:MRKCL) valued at $18,711,471 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 156,577 shares of Merck & Co., Inc.. This represents a change in shares of -1.35% 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 154,467 -2,110 -1.35 18,711 12.64 0.0519
2026-02-17 2025-12-31 13F MERCK COM 58933Y105 156,577 13,999 9.82 16,613 37.52 0.0436
2025-11-14 2025-09-30 13F MERCK COM 58933Y105 142,578 -5,450 -3.68 12,081 2.05 0.0319
2025-08-14 2025-06-30 13F MERCK COM 58933Y105 148,028 -28,704 -16.24 11,838 -26.05 0.0334
2025-05-15 2025-03-31 13F MERCK COM 58933Y105 176,732 -16,659 -8.61 16,006 -17.80 0.0467
2025-02-14 2024-12-31 13F MERCK COM 58933Y105 193,391 -16,728 -7.96 19,474 -18.94 0.0571
2024-11-14 2024-09-30 13F MERCK COM 58933Y105 210,119 -738 -0.35 24,023 -8.54 0.0712
2024-08-15 2024-06-30 13F/A-1 MERCK COM 58933Y105 210,857 2,776 1.33 26,266 -4.37 0.0842
2024-08-14 2024-06-30 13F MERCK COM 58933Y105 210,857 2,776 26,266 0.0842
2024-05-15 2024-03-31 13F MERCK COM 58933Y105 208,081 -2,425 -1.15 27,465 19.64 0.0890
2024-02-13 2023-12-31 13F MERCK COM 58933Y105 210,506 -6,449 -2.97 22,957 2.78 0.0796
2023-11-14 2023-09-30 13F MERCK COM 58933Y105 216,955 -5,219 -2.35 22,336 -12.88 0.0825
2023-08-14 2023-06-30 13F MERCK COM 58933Y105 222,174 -6,889 -3.01 25,637 5.20 0.0939
2023-05-15 2023-03-31 13F MERCK COM 58933Y105 229,063 -8,321 -3.51 24,370 -7.47 0.0935
2023-02-14 2022-12-31 13F MERCK COM 58933Y105 237,384 -1,359 -0.57 26,338 28.10 0.0965
2022-11-14 2022-09-30 13F MERCK COM 58933Y105 238,743 -7,911 -3.21 20,561 -8.56 0.0871
2022-08-15 2022-06-30 13F MERCK COM 58933Y105 246,654 -8,685 -3.40 22,487 7.34 0.0906
2022-05-16 2022-03-31 13F MERCK COM 58933Y105 255,339 -4,572 -1.76 20,950 5.18 0.0685
2022-02-14 2021-12-31 13F MERCK COM 58933Y105 259,911 -2,566 -0.98 19,919 1.04 0.0656
2021-11-15 2021-09-30 13F MERCK COM 58933Y105 262,477 -5,029 -1.88 19,714 -5.24 0.0726
2021-08-16 2021-06-30 13F MERCK COM 58933Y105 267,506 6,812 2.61 20,804 3.52 0.0759
2021-05-14 2021-03-31 13F MERCK & CO. COM 58933Y105 260,694 85,415 48.73 20,097 40.17 0.0866
2021-02-16 2020-12-31 13F MERCK & CO. COM 58933Y105 175,279 1,294 0.74 14,338 -0.65 0.0686
2020-11-12 2020-09-30 13F MERCK COMMON 58933Y105 173,985 -4,924 -2.75 14,432 4.32 0.0744
2020-08-14 2020-06-30 13F MERCK COMMON 58933Y105 178,909 -5,350 -2.90 13,835 -2.41 0.0800
2020-05-06 2020-03-31 13F MERCK COMMON 58933Y105 184,259 399 0.22 14,177 -15.22 0.0919
2020-02-13 2019-12-31 13F MERCK COMMON 58933Y105 183,860 4,025 2.24 16,722 10.46 0.0839
2019-11-13 2019-09-30 13F MERCK COMMON 58933Y105 179,835 -11,118 -5.82 15,138 -5.45 0.0834
2019-08-16 2019-06-30 13F MERCK COMMON 58933Y105 190,953 3,600 1.92 16,011 2.75 0.0889
2019-04-12 2019-03-31 13F MERCK COMMON 58933Y105 187,353 -9,479 -4.82 15,582 3.60 0.0900
2019-01-30 2018-12-31 13F MERCK COMMON 58933Y105 196,832 -3,153 -1.58 15,040 6.01 0.0936
2018-10-15 2018-09-30 13F MERCK COMMON 58933Y105 199,985 -4,122 -2.02 14,187 14.51 0.0756
2018-08-01 2018-06-30 13F MERCK COMMON 58933Y105 204,107 -9,167 -4.30 12,389 6.65 0.0714
2018-04-20 2018-03-31 13F MERCK COMMON 58933Y105 213,274 -6,768 -3.08 11,617 -6.18 0.0661
2018-01-22 2017-12-31 13F MERCK COMMON 58933Y105 220,042 -11,460 -4.95 12,382 -16.47 0.0678
2017-10-25 2017-09-30 13F MERCK COMMON 58933Y105 231,502 4,703 2.07 14,823 1.98 0.0849
2017-08-10 2017-06-30 13F/A-2 MERCK COMMON 58933Y105 226,799 -5,058 -2.18 14,535 -1.34 0.0848
2017-08-01 2017-06-30 13F/A-1 MERCK COMMON 58933Y105 226,800 1 14,535 0.0848
2017-07-28 2017-06-30 13F MERCK COMMON 58933Y105 226,799 -5,058 14,535
2017-04-25 2017-03-31 13F/A-1 MERCK COMMON 58933Y105 231,857 -5,410 -2.28 14,732 5.47 0.0875
2017-04-24 2017-03-31 13F MERCK COMMON 58933Y105 243,433 15,192
2017-01-25 2016-12-31 13F MERCK COMMON 58933Y105 237,267 -6,166 -2.53 13,968 -8.06 0.0849
2016-10-20 2016-09-30 13F MERCK COMMON 58933Y105 243,433 -10,149 -4.00 15,192 4.00 0.0927
2016-07-14 2016-06-30 13F MERCK COMMON 58933Y105 253,582 -3,482 -1.35 14,608 7.40 0.0897
2016-04-22 2016-03-31 13F MERCK COMMON 58933Y105 257,064 37,835 17.26 13,601 17.46 0.0837
2016-01-20 2015-12-31 13F MERCK COMMON 58933Y105 219,229 6,566 3.09 11,579 10.24 0.0711
2015-10-26 2015-09-30 13F MERCK COMMON 58933Y105 212,663 8,644 4.24 10,503 -9.57 0.0675
2015-07-17 2015-06-30 13F MERCK COMMON 58933Y105 204,019 1,305 0.64 11,614 -0.33 0.0686
2015-04-30 2015-03-31 13F MERCK COMMON 58933Y105 202,714 28,087 16.08 11,652 17.50 0.0671
2015-01-20 2014-12-31 13F MERCK COMMON 58933Y105 174,627 -3,204 -1.80 9,917 -5.92 0.0561
2014-10-23 2014-09-30 13F MERCK COMMON 58933Y105 177,831 1,132 0.64 10,541 3.12 0.0613
2014-08-14 2014-06-30 13F/A-1 MERCK COMMON 58933Y105 176,699 -11,660 -6.19 10,222 -4.40 0.0648
2014-05-16 2014-03-31 13F MERCK COMMON 58933Y105 188,359 -40,400 -17.66 10,693 -6.60 0.0704
2014-02-04 2013-12-31 13F MERCK COMMON 58933Y105 228,759 2,617 1.16 11,449 6.34 0.0757
2013-10-29 2013-09-30 13F MERCK COMMON 58933Y105 226,142 337 0.15 10,766 -1.37 0.0752
2013-08-13 2013-06-30 13F MERCK COMMON 58933Y105 225,805 225,805 10,915 0.0751
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.