Merck & Co., Inc.
BG ˙ BUL ˙ US58933Y1055
SecurityBG:6MK / Merck & Co., Inc.
InstitutionTamar Securities, LLC
Latest Disclosed Ownership2,423 shares
Latest Disclosed Value $ 291,441
Tamar Securities, LLC reports 4.35% increase in ownership of 6MK / Merck & Co., Inc.

On May 14, 2026 - Tamar Securities, LLC filed a 13F-HR form disclosing ownership of 2,423 shares of Merck & Co., Inc. (BG:6MK) valued at $291,441 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 2,322 shares of Merck & Co., Inc.. This represents a change in shares of 4.35% 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)
2026-05-14 2026-03-31 13F MERCK COM 58933Y105 2,423 101 4.35 291 19.26 0.0312
2026-02-13 2025-12-31 13F MERCK COM 58933Y105 2,322 2,322 244 0.0258
2025-08-11 2025-06-30 13F MERCK COM 58933Y105 0 -2,317 -100.00 0 -100.00
2025-05-15 2025-03-31 13F MERCK COM 58933Y105 2,317 59 2.61 208 -7.59 0.0282
2025-01-22 2024-12-31 13F MERCK COM 58933Y105 2,258 -5 -0.22 225 -12.50 0.0310
2024-10-16 2024-09-30 13F MERCK COM 58933Y105 2,263 86 3.95 257 -4.83 0.0361
2024-10-10 2024-06-30 13F MERCK COM 58933Y105 2,177 16 0.74 270 -5.61 0.0437
2024-05-13 2024-03-31 13F MERCK COM 58933Y105 2,161 7 0.32 285 21.79 0.0481
2024-01-25 2023-12-31 13F MERCK COM 58933Y105 2,154 -22 -1.01 235 4.93 0.0461
2023-11-14 2023-09-30 13F MERCK COM 58933Y105 2,176 122 5.94 224 -5.51 0.0540
2024-10-10 2023-06-30 13F MERCK COM 58933Y105 2,054 6 0.29 237 8.76 0.0583
2024-10-10 2023-03-31 13F MERCK COM 58933Y105 2,048 -633 -23.61 218 -26.94 0.0626
2023-02-10 2022-12-31 13F MERCK COM 58933Y105 2,681 -43 -1.58 297 26.38 0.0944
2022-11-07 2022-09-30 13F MERCK COM 58933Y105 2,724 -36 -1.30 235 -6.75 0.0752
2022-08-05 2022-06-30 13F MERCK COM 58933Y105 2,760 126 4.78 252 16.67 0.0827
2022-04-27 2022-03-31 13F MERCK COM 58933Y105 2,634 2,634 216 0.0603
2021-10-19 2021-09-30 13F MERCK COM 58933Y105 0 -2,692 -100.00 0 -100.00
2021-08-06 2021-06-30 13F MERCK COM 58933Y105 2,692 56 2.12 209 2.96 0.0805
2021-05-11 2021-03-31 13F MERCK & CO. COM 58933Y105 2,636 107 4.23 203 -1.93 0.0785
2021-01-27 2020-12-31 13F MERCK & CO. COM 58933Y105 2,529 -15 -0.59 207 -1.90 0.1177
2020-11-05 2020-09-30 13F MERCK & CO. COM 58933Y105 2,544 2,544 211 0.1311
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.