Merck & Co., Inc.
MX ˙ BMV ˙ US58933Y1055
SecurityMX:MRK / Merck & Co., Inc.
InstitutionHeadinvest, Llc
Latest Disclosed Ownership14,276 shares
Latest Disclosed Value $ 1,717,260
Headinvest, Llc reports 10.76% decrease in ownership of MRK / Merck & Co., Inc.

On May 15, 2026 - Headinvest, Llc filed a 13F-HR form disclosing ownership of 14,276 shares of Merck & Co., Inc. (MX:MRK) valued at $1,717,260 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 2, 2026 disclosing 15,998 shares of Merck & Co., Inc.. This represents a change in shares of -10.76% 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 14,276 -1,722 -10.76 1,717 2.02 0.3523
2026-02-02 2025-12-31 13F MERCK COM 58933Y105 15,998 3,062 23.67 1,684 55.12 0.3349
2025-11-14 2025-09-30 13F MERCK COM 58933Y105 12,936 -672 -4.94 1,086 0.74 0.2244
2025-08-14 2025-06-30 13F MERCK COM 58933Y105 13,608 -1,718 -11.21 1,077 -21.67 0.2295
2025-05-15 2025-03-31 13F MERCK COM 58933Y105 15,326 -6,036 -28.26 1,376 -35.29 0.2675
2025-02-18 2024-12-31 13F MERCK COM 58933Y105 21,362 -493 -2.26 2,125 -14.35 0.4011
2024-11-15 2024-09-30 13F MERCK COM 58933Y105 21,855 -410 -1.84 2,482 -9.98 0.4593
2024-08-14 2024-06-30 13F MERCK COM 58933Y105 22,265 -812 -3.52 2,756 -9.49 0.5428
2024-08-14 2024-03-31 13F MERCK COM 58933Y105 23,077 -2,430 -9.53 3,045 9.53 0.5943
2024-02-12 2023-12-31 13F MERCK & CO INC COM Stock 58933Y105 25,507 -551 -2.11 2,781 4.04 0.5784
2023-12-11 2023-09-30 13F MERCK & CO INC COM Stock 58933Y105 26,058 -186 -0.71 2,672 -5.21 0.5805
2023-08-23 2023-06-30 13F MERCK & CO INC COM Stock 58933Y105 26,244 -1,348 -4.89 2,820 -3.95 0.6077
2023-05-17 2023-03-31 13F MERCK & CO INC COM Stock 58933Y105 27,592 549 2.03 2,936 -2.17 0.6439
2023-02-13 2022-12-31 13F MERCK & CO INC COM Stock 58933Y105 27,043 -374 -1.36 3,000 27.06 0.6715
2022-12-28 2022-09-30 13F MERCK & CO INC COM Stock 58933Y105 27,417 -400 -1.44 2,361 -6.90 0.5656
2022-08-12 2022-06-30 13F MERCK & CO INC COM Stock 58933Y105 27,817 550 2.02 2,536 13.37 0.5643
2022-05-13 2022-03-31 13F MERCK & CO INC COM Stock 58933Y105 27,267 23 0.08 2,237 7.14 0.4275
2022-02-11 2021-12-31 13F MERCK & CO INC COM Stock 58933Y105 27,244 -109 -0.40 2,088 1.66 0.3704
2021-11-16 2021-09-30 13F MERCK & CO INC COM Stock 58933Y105 27,353 -168 -0.61 2,054 -4.02 0.3895
2021-08-30 2021-06-30 13F MERCK & CO INC COM Stock 58933Y105 27,521 183 0.67 2,140 1.57 0.4070
2021-05-13 2021-03-31 13F MERCK & CO. INC COM Stock 58933Y105 27,338 701 2.63 2,107 -3.30 0.4300
2021-02-16 2020-12-31 13F/A-1 Merck COM 58933Y105 26,637 5,309 24.89 2,179 23.18 0.4625
2021-02-16 2020-12-31 13F Merck COM 58933Y105 21,328 1,769 0.5112
2020-11-24 2020-09-30 13F Merck COM 58933Y105 21,328 1,020 5.02 1,769 12.68 0.5112
2020-08-12 2020-06-30 13F Merck COM 58933Y105 20,308 383 1.92 1,570 2.41 0.4946
2020-05-12 2020-03-31 13F/A-1 Merck COM 58933Y105 19,925 967 5.10 1,533 -11.08 0.5738
2020-05-11 2020-03-31 13F Merck COM 58933Y105 25,431 6,473 2,115 592,589.6870
2020-02-14 2019-12-31 13F Merck COM 58933Y105 18,958 -7,068 -27.16 1,724 -21.31 0.4950
2019-11-21 2019-09-30 13F Merck COM 58933Y105 26,026 860 3.42 2,191 3.84 0.6644
2019-08-22 2019-06-30 13F Merck COM 58933Y105 25,166 -265 -1.04 2,110 -0.24 0.5968
2019-05-15 2019-03-31 13F Merck COM 58933Y105 25,431 -25,140 -49.71 2,115 -45.26 0.5926
2019-02-22 2018-12-31 13F Merck COM 58933Y105 50,571 24,986 97.66 3,864 112.89 0.6120
2018-11-14 2018-09-30 13F Merck COM 58933Y105 25,585 126 0.49 1,815 17.48 0.5222
2018-08-09 2018-06-30 13F Merck COM 58933Y105 25,459 -361 -1.40 1,545 9.89 0.4710
2018-04-09 2018-03-31 13F Merck COM 58933Y105 25,820 -105 -0.41 1,406 -3.63 0.4509
2018-01-30 2017-12-31 13F Merck COM 58933Y105 25,925 -375 -1.43 1,459 0.69 0.4500
2017-11-13 2017-09-30 13F Merck COM 58933Y105 26,300 -300 -1.13 1,449 -15.01 0.4538
2017-07-18 2017-06-30 13F Merck COM 58933Y105 26,600 70 0.26 1,705 1.13 0.5617
2017-04-25 2017-03-31 13F Merck COM 58933Y105 26,530 560 2.16 1,686 10.27 0.5666
2017-01-24 2016-12-31 13F Merck COM 58933Y105 25,970 -75 -0.29 1,529 -8.11 0.5686
2016-10-11 2016-09-30 13F Merck COM 58933Y105 26,045 -200 -0.76 1,664 10.05 0.5901
2016-07-26 2016-06-30 13F Merck COM 58933Y105 26,245 200 0.77 1,512 9.72 0.5721
2016-04-21 2016-03-31 13F Merck COM 58933Y105 26,045 1,575 6.44 1,378 6.57 0.5393
2016-01-20 2015-12-31 13F Merck COM 58933Y105 24,470 -50 -0.20 1,293 6.77 0.5240
2015-10-16 2015-09-30 13F Merck COM 58933Y105 24,520 0 0.00 1,211 -13.25 0.4862
2015-08-07 2015-06-30 13F Merck COM 58933Y105 24,520 -699 -2.77 1,396 -3.72 0.5169
2015-05-14 2015-03-31 13F Merck COM 58933Y105 25,219 -68 -0.27 1,450 0.97 0.5203
2015-02-10 2014-12-31 13F Merck COM 58933Y105 25,287 -25 -0.10 1,436 -2.11 0.5726
2014-11-12 2014-09-30 13F Merck COM 58933Y105 25,312 1,843 7.85 1,467 8.03 0.5863
2014-07-31 2014-06-30 13F Merck COM 58933Y105 23,469 2 0.01 1,358 1.95 0.5494
2014-05-07 2014-03-31 13F Merck COM 58933Y105 23,467 701 3.08 1,332 16.94 0.5735
2014-02-12 2013-12-31 13F Merck COM 58933Y105 22,766 -329 -1.42 1,139 3.55 0.4800
2013-11-15 2013-09-30 13F Merck COM 58933Y105 23,095 -735 -3.08 1,100 -0.63 0.4797
2013-07-30 2013-06-30 13F Merck COM 58933Y105 23,830 23,830 1,107 0.4871
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.