Merck & Co., Inc.
MX ˙ BMV ˙ US58933Y1055
SecurityMX:MRK / Merck & Co., Inc.
InstitutionBigSur Wealth Management LLC
Latest Disclosed Ownership30,960 shares
Latest Disclosed Value $ 3,750,494
BigSur Wealth Management LLC reports 28.08% decrease in ownership of MRK / Merck & Co., Inc.

On April 22, 2026 - BigSur Wealth Management LLC filed a 13F-HR form disclosing ownership of 30,960 shares of Merck & Co., Inc. (MX:MRK) valued at $3,750,494 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 27, 2026 disclosing 43,050 shares of Merck & Co., Inc.. This represents a change in shares of -28.08% 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)
2026-04-22 2026-03-31 13F MERCK COM 58933Y105 30,960 -12,090 -28.08 3,750 -17.91 1.0495
2026-01-27 2025-12-31 13F MERCK COM 58933Y105 43,050 0 0.00 4,568 25.08 1.1081
2025-10-14 2025-09-30 13F MERCK COM 58933Y105 43,050 -12,360 -22.31 3,652 -17.58 0.8945
2025-07-15 2025-06-30 13F MERCK COM 58933Y105 55,410 0 0.00 4,431 -11.70 1.1186
2025-04-16 2025-03-31 13F MERCK COM 58933Y105 55,410 -300 -0.54 5,019 -10.02 1.3595
2025-01-16 2024-12-31 13F MERCK COM 58933Y105 55,710 12,000 27.45 5,577 11.61 1.5938
2024-10-16 2024-09-30 13F MERCK COM 58933Y105 43,710 5,592 14.67 4,997 5.24 1.3766
2024-07-22 2024-06-30 13F MERCK COM 58933Y105 38,118 2,450 6.87 4,748 0.32 1.4538
2024-05-22 2024-03-31 13F MERCK COM 58933Y105 35,668 9,270 35.12 4,734 63.32 1.4834
2024-02-12 2023-12-31 13F MERCK COM 58933Y105 26,398 -1,000 -3.65 2,898 2.04 1.3795
2023-11-13 2023-09-30 13F MERCK COM 58933Y105 27,398 -735 -2.61 2,841 -13.10 1.4319
2023-08-14 2023-06-30 13F MERCK COM 58933Y105 28,133 -2,270 -7.47 3,268 0.37 1.5620
2023-05-12 2023-03-31 13F MERCK COM 58933Y105 30,403 1,000 3.40 3,257 -0.82 1.5280
2023-02-09 2022-12-31 13F MERCK COM 58933Y105 29,403 -2,637 -8.23 3,284 18.05 1.5822
2022-11-09 2022-09-30 13F MERCK COM 58933Y105 32,040 -488 -1.50 2,781 -6.93 1.4065
2022-08-10 2022-06-30 13F MERCK COM 58933Y105 32,528 0 0.00 2,988 11.04 1.4076
2022-05-05 2022-03-31 13F MERCK COM 58933Y105 32,528 33 0.10 2,691 7.08 1.0485
2022-02-07 2021-12-31 13F MERCK COM 58933Y105 32,495 0 0.00 2,513 2.07 0.9831
2021-11-01 2021-09-30 13F MERCK COM 58933Y105 32,495 0 0.00 2,462 -3.38 1.1058
2021-07-29 2021-06-30 13F MERCK COM 58933Y105 32,495 -1,300 -3.85 2,548 -3.01 1.1498
2021-05-06 2021-03-31 13F MERCK & CO. COM 58933Y105 33,795 800 2.42 2,627 -3.42 1.3482
2021-01-22 2020-12-31 13F MERCK & CO. COM 58933Y105 32,995 0 0.00 2,720 -1.34 1.5359
2020-10-30 2020-09-30 13F MERCK & CO. COM 58933Y105 32,995 5,950 22.00 2,757 30.79 1.7561
2020-07-31 2020-06-30 13F MERCK & CO. COM 58933Y105 27,045 -6,300 -18.89 2,108 -18.52 1.5072
2020-05-05 2020-03-31 13F MERCK & CO. COM 58933Y105 33,345 -2,800 -7.75 2,587 -21.82 1.9392
2020-01-30 2019-12-31 13F MERCK COM 58933Y105 36,145 14,500 66.99 3,309 80.43 1.8697
2019-11-05 2019-09-30 13F MERCK COM 58933Y105 21,645 920 4.44 1,834 3.73 1.2358
2019-07-05 2019-06-30 13F MERCK COM 58933Y105 20,725 -2,420 -10.46 1,768 -8.77 1.2335
2019-04-05 2019-03-31 13F MERCK COM 58933Y105 23,145 0 0.00 1,938 8.82 1.2710
2019-02-01 2018-12-31 13F MERCK COM 58933Y105 23,145 2,440 11.78 1,781 20.42 1.2656
2018-10-23 2018-09-30 13F MERCK COM 58933Y105 20,705 820 4.12 1,479 21.53 0.9254
2018-08-01 2018-06-30 13F MERCK COM 58933Y105 19,885 2,570 14.84 1,217 27.97 0.8863
2018-05-02 2018-03-31 13F MERCK COM 58933Y105 17,315 1,280 7.98 951 4.51 0.6780
2018-02-01 2017-12-31 13F MERCK COM 58933Y105 16,035 500 3.22 910 -9.18 0.9045
2017-11-02 2017-09-30 13F MERCK COM 58933Y105 15,535 0 0.00 1,002 2.66 1.0071
2017-08-14 2017-06-30 13F MERCK COM 58933Y105 15,535 0 0.00 976 -0.71 0.9901
2017-05-12 2017-03-31 13F MERCK COM 58933Y105 15,535 -1,000 -6.05 983 0.20 1.0635
2017-02-09 2016-12-31 13F MERCK COM 58933Y105 16,535 16,535 981 1.3123
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.