Merck & Co., Inc.
MX ˙ BMV ˙ US58933Y1055
SecurityMX:MRK / Merck & Co., Inc.
InstitutionAristotle Atlantic Partners, Llc
Latest Disclosed Ownership552,486 shares
Latest Disclosed Value $ 66,458,541
Aristotle Atlantic Partners, Llc reports 11.25% increase in ownership of MRK / Merck & Co., Inc.

On May 15, 2026 - Aristotle Atlantic Partners, Llc filed a 13F-HR form disclosing ownership of 552,486 shares of Merck & Co., Inc. (MX:MRK) valued at $66,458,541 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 496,610 shares of Merck & Co., Inc.. This represents a change in shares of 11.25% 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)
2026-05-15 2026-03-31 13F MERCK COM 58933Y105 552,486 55,876 11.25 66,459 27.14 1.7581
2026-02-17 2025-12-31 13F MERCK COM 58933Y105 496,610 0 0.00 52,273 25.42 2.3914
2025-11-14 2025-09-30 13F MERCK COM 58933Y105 496,610 0 0.00 41,680 6.03 1.2091
2025-08-14 2025-06-30 13F MERCK COM 58933Y105 496,610 0 0.00 39,312 -11.81 1.1957
2025-05-15 2025-03-31 13F MERCK COM 58933Y105 496,610 0 0.00 44,576 -9.77 1.5042
2025-02-14 2024-12-31 13F MERCK COM 58933Y105 496,610 0 0.00 49,403 -12.40 1.5533
2024-11-14 2024-09-30 13F MERCK COM 58933Y105 496,610 0 0.00 56,395 -8.27 1.7534
2024-08-14 2024-06-30 13F MERCK COM 58933Y105 496,610 -4,000 -0.80 61,480 -6.93 1.9921
2024-05-15 2024-03-31 13F MERCK COM 58933Y105 500,610 -17,000 -3.28 66,055 17.06 2.1561
2024-02-14 2023-12-31 13F MERCK COM 58933Y105 517,610 0 0.00 56,430 5.90 1.9859
2023-11-14 2023-09-30 13F MERCK COM 58933Y105 517,610 -9,200 -1.75 53,288 -12.34 2.1338
2023-08-14 2023-06-30 13F MERCK COM 58933Y105 526,810 0 0.00 60,789 8.46 2.2893
2023-05-15 2023-03-31 13F MERCK COM 58933Y105 526,810 0 0.00 56,047 -4.11 2.8823
2023-02-14 2022-12-31 13F MERCK COM 58933Y105 526,810 0 0.00 58,450 28.83 3.2738
2022-11-14 2022-09-30 13F MERCK COM 58933Y105 526,810 0 0.00 45,369 -5.54 2.7599
2022-08-15 2022-06-30 13F MERCK COM 58933Y105 526,810 -500 -0.09 48,029 11.01 3.6941
2022-05-16 2022-03-31 13F MERCK COM 58933Y105 527,310 0 0.00 43,266 7.06 2.6775
2022-02-14 2021-12-31 13F MERCK COM 58933Y105 527,310 -50,900 -8.80 40,413 -6.94 2.3460
2021-11-15 2021-09-30 13F MERCK COM 58933Y105 578,210 0 0.00 43,429 -3.42 2.8736
2021-08-16 2021-06-30 13F MERCK COM 58933Y105 578,210 0 0.00 44,967 0.88 2.9660
2021-05-17 2021-03-31 13F MERCK & CO. COM 58933Y105 578,210 0 0.00 44,574 -5.76 3.2596
2021-02-16 2020-12-31 13F MERCK & CO. COM 58933Y105 578,210 -1,100 -0.19 47,298 -1.57 3.6500
2020-11-16 2020-09-30 13F MERCK & CO. COM 58933Y105 579,310 -27,700 -4.56 48,053 2.37 4.2328
2020-08-14 2020-06-30 13F MERCK & CO. COM 58933Y105 607,010 0 0.00 46,940 0.51 4.5088
2020-05-14 2020-03-31 13F MERCK & CO. COM 58933Y105 607,010 -45,000 -6.90 46,703 -21.24 7.1330
2020-02-13 2019-12-31 13F MERCK COM 58933Y105 652,010 0 0.00 59,301 8.04 7.5730
2019-11-14 2019-09-30 13F MERCK COM 58933Y105 652,010 -12,000 -1.81 54,886 -1.42 15.8061
2019-08-13 2019-06-30 13F MERCK COM 58933Y105 664,010 -7,000 -1.04 55,677 -0.23 16.1868
2019-05-15 2019-03-31 13F MERCK COM 58933Y105 671,010 -10,000 -1.47 55,808 7.25 16.9579
2019-02-13 2018-12-31 13F MERCK COM 58933Y105 681,010 0 0.00 52,036 406.19 18.3393
2018-11-14 2018-09-30 13F MERCK COM 58933Y105 681,010 -14,000 -2.01 10,280 -75.63 6.2829
2018-08-14 2018-06-30 13F MERCK COM 58933Y105 695,010 0 0.00 42,185 11.43 14.6281
2018-09-07 2018-03-31 13F/A-1 MERCK COM 58933Y105 695,010 -38,177 -5.21 37,857 -8.24 13.6636
2018-05-14 2018-03-31 13F MERCK COM 58933Y105 4,900 -728,287 267
2018-09-07 2017-12-31 13F/A-1 MERCK COM 58933Y105 733,187 733,187 41,257 14.8087
2018-02-14 2017-12-31 13F MERCK COM 58933Y105 733,187 41,257 14.7906
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.