Merck & Co., Inc.
US ˙ NYSE ˙ US58933Y1055

SecurityMRK / Merck & Co., Inc.
InstitutionPrincipal Street Partners, LLC
Latest Disclosed Ownership2,728 shares
Latest Disclosed Value $ 328,165
Principal Street Partners, LLC ownership in MRK / Merck & Co., Inc.

On May 15, 2026 - Principal Street Partners, LLC filed a 13F-HR form disclosing ownership of 2,728 shares of Merck & Co., Inc. (US:MRK) valued at $328,151 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 2,728 shares of Merck & Co., Inc.. This represents a change in shares of 0.00% during the quarter. The current value of the position is $312,902 USD.

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 Common stock 58933Y105 2,728 0 0.00 328 14.29 0.0536
2026-02-17 2025-12-31 13F MERCK Common stock 58933Y105 2,728 -913 -25.08 287 -5.90 0.0484
2025-11-14 2025-09-30 13F MERCK Common stock 58933Y105 3,641 -2,881 -44.17 306 -40.89 0.0488
2025-08-14 2025-06-30 13F MERCK Common stock 58933Y105 6,522 -5,543 -45.94 516 -52.31 0.0506
2025-05-15 2025-03-31 13F MERCK Common stock 58933Y105 12,065 3,458 40.18 1,083 26.40 0.2014
2025-02-18 2024-12-31 13F MERCK Common stock 58933Y105 8,607 -3,841 -30.86 856 -42.59 0.1684
2024-11-13 2024-09-30 13F MERCK Common stock 58933Y105 12,448 3,796 43.87 1,491 39.22 0.2439
2024-08-14 2024-06-30 13F MERCK Common stock 58933Y105 8,652 -546 -5.94 1,071 -11.19 0.1919
2024-05-15 2024-03-31 13F MERCK Common stock 58933Y105 9,198 -339 -3.55 1,207 16.07 0.2281
2024-02-07 2023-12-31 13F MERCK Common stock 58933Y105 9,537 -214 -2.19 1,040 3.59 0.2508
2023-11-01 2023-09-30 13F MERCK Common stock 58933Y105 9,751 -2,462 -20.16 1,004 -28.97 0.1989
2023-08-21 2023-06-30 13F/A-1 MERCK Common stock 58933Y105 12,213 -200 -1.61 1,412 6.73 0.3356
2023-08-15 2023-06-30 13F MERCK Common stock 58933Y105 12,413 0 1,323 0.3345
2023-05-11 2023-03-31 13F MERCK Common stock 58933Y105 12,413 -2,208 -15.10 1,323 -18.53 0.3345
2023-02-15 2022-12-31 13F MERCK Common stock 58933Y105 14,621 -430 -2.86 1,625 25.02 0.4094
2022-11-14 2022-09-30 13F MERCK Common stock 58933Y105 15,051 62 0.41 1,299 -5.11 0.3462
2022-08-15 2022-06-30 13F MERCK Common stock 58933Y105 14,989 -1,698 -10.18 1,369 -0.15 0.3546
2022-05-05 2022-03-31 13F Merck Common stock 58933Y105 16,687 312 1.91 1,371 9.07 0.3143
2022-02-07 2021-12-31 13F Merck Common stock 58933Y105 16,375 9,939 154.43 1,257 158.64 0.3026
2021-11-10 2021-09-30 13F Merck Common stock 58933Y105 6,436 229 3.69 486 0.41 0.1324
2021-08-10 2021-06-30 13F Merck Common stock 58933Y105 6,207 -1,391 -18.31 484 -17.41 0.1277
2021-05-13 2021-03-31 13F Merck Common stock 58933Y105 7,598 4,127 118.90 586 106.34 0.0756
2021-02-16 2020-12-31 13F Merck Common stock 58933Y105 3,471 -216 -5.86 284 -7.19 0.0870
2020-11-12 2020-09-30 13F Merck Common stock 58933Y105 3,687 74 2.05 306 9.68 0.1075
2020-08-14 2020-06-30 13F Merck Common stock 58933Y105 3,613 -38 -1.04 279 -0.71 0.1042
2020-05-14 2020-03-31 13F Merck Common stock 58933Y105 3,651 3,651 281 0.1179
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.