Merck & Co., Inc.
MX ˙ BMV ˙ US58933Y1055
SecurityMX:MRK / Merck & Co., Inc.
InstitutionStamos Capital Partners, L.p.
Latest Disclosed Ownership170,384 shares
Latest Disclosed Value $ 20,495,491
Stamos Capital Partners, L.p. reports 8.79% decrease in ownership of MRK / Merck & Co., Inc.

On May 14, 2026 - Stamos Capital Partners, L.p. filed a 13F-HR form disclosing ownership of 170,384 shares of Merck & Co., Inc. (MX:MRK) valued at $20,495,491 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 12, 2026 disclosing 186,805 shares of Merck & Co., Inc.. This represents a change in shares of -8.79% 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)
2026-05-14 2026-03-31 13F MERCK COM 58933Y105 170,384 -16,421 -8.79 20,495 4.23 3.2041
2026-02-12 2025-12-31 13F MERCK COM 58933Y105 186,805 -13,254 -6.63 19,663 17.11 3.1597
2025-11-13 2025-09-30 13F MERCK COM 58933Y105 200,059 -26,846 -11.83 16,791 -6.52 3.1677
2025-08-14 2025-06-30 13F MERCK COM 58933Y105 226,905 112,671 98.63 17,962 75.18 3.2219
2025-05-14 2025-03-31 13F MERCK COM 58933Y105 114,234 -9,446 -7.64 10,254 -16.66 2.6820
2025-02-13 2024-12-31 13F MERCK COM 58933Y105 123,680 29,500 31.32 12,304 15.04 2.8873
2024-11-13 2024-09-30 13F MERCK COM 58933Y105 94,180 24,190 34.56 10,695 23.44 2.5168
2024-08-13 2024-06-30 13F MERCK COM 58933Y105 69,990 -2,150 -2.98 8,665 -8.97 1.8384
2024-05-14 2024-03-31 13F MERCK COM 58933Y105 72,140 -13,860 -16.12 9,519 1.53 2.1608
2024-02-13 2023-12-31 13F MERCK COM 58933Y105 86,000 -500 -0.58 9,376 5.28 2.5439
2023-11-13 2023-09-30 13F MERCK COM 58933Y105 86,500 12,290 16.56 8,905 3.99 1.9838
2023-08-11 2023-06-30 13F MERCK COM 58933Y105 74,210 -2,000 -2.62 8,563 5.62 2.0029
2023-05-12 2023-03-31 13F MERCK COM 58933Y105 76,210 15,910 26.38 8,108 21.18 2.0918
2023-02-13 2022-12-31 13F MERCK COM 58933Y105 60,300 -37,830 -38.55 6,690 -20.84 2.1173
2022-11-14 2022-09-30 13F MERCK COM 58933Y105 98,130 5,830 6.32 8,451 0.43 2.1491
2022-08-12 2022-06-30 13F MERCK COM 58933Y105 92,300 0 0.00 8,415 11.12 2.5448
2022-05-13 2022-03-31 13F MERCK COM 58933Y105 92,300 1,500 1.65 7,573 8.82 2.5279
2022-02-14 2021-12-31 13F MERCK COM 58933Y105 90,800 26,050 40.23 6,959 43.10 3.2285
2021-11-12 2021-09-30 13F MERCK COM 58933Y105 64,750 0 0.00 4,863 -3.44 2.7198
2021-08-13 2021-06-30 13F MERCK COM 58933Y105 64,750 4,450 7.38 5,036 8.32 2.6544
2021-05-14 2021-03-31 13F MERCK & CO. COM 58933Y105 60,300 0 0.00 4,649 -5.76 2.3468
2021-02-12 2020-12-31 13F MERCK & CO. COM 58933Y105 60,300 30,300 101.00 4,933 98.19 2.1039
2020-11-16 2020-09-30 13F MERCK & CO. COM 58933Y105 30,000 0 0.00 2,489 7.28 0.9248
2020-08-14 2020-06-30 13F MERCK & CO. COM 58933Y105 30,000 -22,111 -42.43 2,320 -42.13 1.3286
2020-05-15 2020-03-31 13F MERCK & CO. COM 58933Y105 52,111 19,171 58.20 4,009 33.81 2.1110
2020-02-14 2019-12-31 13F MERCK COM 58933Y105 32,940 -7,560 -18.67 2,996 -12.11 2.4174
2019-11-14 2019-09-30 13F MERCK COM 58933Y105 40,500 16,700 70.17 3,409 69.01 3.0309
2019-08-14 2019-06-30 13F MERCK COM 58933Y105 23,800 -4,200 -15.00 2,017 -11.77 2.0177
2019-05-10 2019-03-31 13F MERCK COM 58933Y105 28,000 -7,000 -20.00 2,286 -14.51 2.9297
2019-02-14 2018-12-31 13F MERCK COM 58933Y105 35,000 35,000 2,674 2.0164
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.