Merck & Co., Inc.
MX ˙ BMV ˙ US58933Y1055
SecurityMX:MRK / Merck & Co., Inc.
InstitutionDiamant Asset Management, Inc.
Latest Disclosed Ownership2,068,387 shares
Latest Disclosed Value $ 2,068,387
Diamant Asset Management, Inc. reports 12,130.29% increase in ownership of MRK / Merck & Co., Inc.

On April 22, 2026 - Diamant Asset Management, Inc. filed a 13F-HR form disclosing ownership of 2,068,387 shares of Merck & Co., Inc. (MX:MRK) valued at $2,068,387 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 6, 2026 disclosing 16,912 shares of Merck & Co., Inc.. This represents a change in shares of 12,130.29% 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.

Upgrade to unlock premium data and export to Excel .

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 & CO INC COM COM 58933Y105 2,068,387 2,051,475 12,130.29 2,068 16.18 1.5071
2026-02-06 2025-12-31 13F MERCK & CO INC COM Com 58933Y105 16,912 -1,600 -8.64 1,780 14.62 1.2869
2025-10-29 2025-09-30 13F MERCK & CO INC COM Comm 58933Y105 18,512 -950 -4.88 1,554 0.84 1.1444
2025-07-16 2025-06-30 13F MERCK & CO INC COM Stock 58933Y105 19,462 -1,000 -4.89 1,541 -16.12 1.1733
2025-05-15 2025-03-31 13F MERCK & CO INC COM COM 58933Y105 20,462 -2,800 -12.04 1,837 -20.66 1.3940
2025-01-22 2024-12-31 13F MERCK & CO INC COM Com 58933Y105 23,262 450 1.97 2,314 -10.66 1.4801
2024-11-20 2024-09-30 13F MERCK & CO INC COM COM 58933Y105 22,812 1,067 4.91 2,591 -3.79 1.6233
2024-08-06 2024-06-30 13F MERCK & CO INC COM Com 58933Y105 21,745 0 0.00 2,692 -6.17 1.8010
2024-04-24 2024-03-31 13F MERCK & CO INC COM Stock 58933Y105 21,745 -320 -1.45 2,869 19.29 1.9920
2024-02-13 2023-12-31 13F MERCK & CO INC COM Stock 58933Y105 22,065 0 0.00 2,406 5.90 1.7821
2023-11-08 2023-09-30 13F MERCK & CO INC COM COM 58933Y105 22,065 525 2.44 2,272 -8.61 1.8682
2023-07-21 2023-06-30 13F MERCK COM 58933Y105 21,540 -160 -0.74 2,486 7.67 1.8996
2023-05-16 2023-03-31 13F/A-1 MERCK Com 58933Y105 21,700 0 0.00 2,309 -4.11 1.8923
2023-05-15 2023-03-31 13F MERCK & CO INC COM COM 58933Y105 21,700 0 2,408 2.1615
2023-02-08 2022-12-31 13F MERCK & CO INC COM COM 58933Y105 21,700 0 0.00 2,408 28.79 2.1615
2022-10-21 2022-09-30 13F MERCK & CO INC COM COM 58933Y105 21,700 1,195 5.83 1,869 0.00 1.8133
2022-08-02 2022-06-30 13F MERCK & CO INC COM Stock 58933Y105 20,505 0 0.00 1,869 11.12 1.6822
2022-05-12 2022-03-31 13F MERCK COM 58933Y105 20,505 475 2.37 1,682 9.58 1.2882
2022-01-31 2021-12-31 13F MERCK COM 58933Y105 20,030 710 3.67 1,535 5.79 1.1221
2021-10-21 2021-09-30 13F MERCK COM 58933Y105 19,320 239 1.25 1,451 -1.36 1.1998
2021-04-19 2021-03-31 13F MERCK &CO. COM 58933Y105 19,081 15,600 448.15 1,471 416.14 1.2922
2021-01-21 2020-12-31 13F MERCK &CO. COM 58933Y105 3,481 859 32.76 285 31.34 0.2535
2020-11-02 2020-09-30 13F MERCK &CO. COM 58933Y105 2,622 -775 -22.81 217 -17.49 0.2086
2020-07-28 2020-06-30 13F MERCK &CO. COM 58933Y105 3,397 0 0.00 263 0.77 0.2769
2020-04-23 2020-03-31 13F MERCK &CO. COM 58933Y105 3,397 0 0.00 261 -15.53 0.3368
2020-02-04 2019-12-31 13F MERCK COM 58933Y105 3,397 -200 -5.56 309 1.98 0.2868
2019-10-31 2019-09-30 13F MERCK COM 58933Y105 3,597 0 0.00 303 0.33 0.3036
2019-07-22 2019-06-30 13F MERCK COM 58933Y105 3,597 0 0.00 302 1.00 0.2989
2019-04-30 2019-03-31 13F MERCK COM 58933Y105 3,597 -3 -0.08 299 8.73 0.3004
2019-01-30 2018-12-31 13F MERCK COM 58933Y105 3,600 0 0.00 275 7.84 0.3085
2018-10-23 2018-09-30 13F MERCK COM 58933Y105 3,600 0 0.00 255 16.44 0.2363
2018-07-24 2018-06-30 13F MERCK COM 58933Y105 3,600 3,600 219 0.2118
2018-05-07 2018-03-31 13F MERCK COM 58933Y105 0 -3,600 -100.00 0 -100.00
2018-02-13 2017-12-31 13F MERCK COM 58933Y105 3,600 3,600 203 0.0297
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.