Merck & Co., Inc.
MX ˙ BMV ˙ US58933Y1055
SecurityMX:MRK / Merck & Co., Inc.
InstitutionL & S Advisors Inc
Latest Disclosed Ownership116,590 shares
Latest Disclosed Value $ 14,024,611
L & S Advisors Inc reports 3.64% decrease in ownership of MRK / Merck & Co., Inc.

On May 11, 2026 - L & S Advisors Inc filed a 13F-HR form disclosing ownership of 116,590 shares of Merck & Co., Inc. (MX:MRK) valued at $14,024,611 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 5, 2026 disclosing 120,990 shares of Merck & Co., Inc.. This represents a change in shares of -3.64% 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)
2026-05-11 2026-03-31 13F MERCK COM 58933Y105 116,590 -4,400 -3.64 14,025 10.12 1.7644
2026-02-05 2025-12-31 13F MERCK COM 58933Y105 120,990 102,592 557.63 12,735 724.81 1.1769
2025-11-07 2025-09-30 13F MERCK COM 58933Y105 18,398 -288 -1.54 1,544 4.39 0.1484
2025-08-08 2025-06-30 13F MERCK COM 58933Y105 18,686 -1,005 -5.10 1,479 -16.30 0.1464
2025-05-09 2025-03-31 13F MERCK COM 58933Y105 19,691 -12 -0.06 1,767 -9.85 0.2181
2025-02-12 2024-12-31 13F MERCK COM 58933Y105 19,703 -79 -0.40 1,960 -12.73 0.2148
2024-11-12 2024-09-30 13F MERCK COM 58933Y105 19,782 -22,130 -52.80 2,246 -56.71 0.2348
2024-08-09 2024-06-30 13F MERCK COM 58933Y105 41,912 -21,431 -33.83 5,189 -37.93 0.5916
2024-05-10 2024-03-31 13F MERCK COM 58933Y105 63,343 46,577 277.81 8,358 357.47 0.9449
2024-02-13 2023-12-31 13F MERCK COM 58933Y105 16,766 13 0.08 1,828 5.97 0.2227
2023-11-13 2023-09-30 13F MERCK COM 58933Y105 16,753 -45,061 -72.90 1,725 -75.83 0.2478
2023-08-14 2023-06-30 13F MERCK COM 58933Y105 61,814 -1,391 -2.20 7,133 6.07 0.9516
2023-05-10 2023-03-31 13F MERCK COM 58933Y105 63,205 -54,358 -46.24 6,724 -48.45 0.9415
2023-02-13 2022-12-31 13F MERCK COM 58933Y105 117,563 52,352 80.28 13,044 132.25 2.4149
2022-11-14 2022-09-30 13F MERCK COM 58933Y105 65,211 -8,618 -11.67 5,616 -16.57 0.9897
2022-08-12 2022-06-30 13F MERCK COM 58933Y105 73,829 30,217 69.29 6,731 88.12 1.1237
2022-05-11 2022-03-31 13F MERCK COM 58933Y105 43,612 -730 -1.65 3,578 5.30 0.4237
2022-02-09 2021-12-31 13F MERCK COM 58933Y105 44,342 -20,058 -31.15 3,398 -29.75 0.3664
2021-11-09 2021-09-30 13F MERCK COM 58933Y105 64,400 19,905 44.74 4,837 39.80 0.5223
2021-08-12 2021-06-30 13F MERCK COM 58933Y105 44,495 -95 -0.21 3,460 0.67 0.3723
2021-05-10 2021-03-31 13F MERCK COM 58933Y105 44,590 -16,761 -27.32 3,437 -31.52 0.3903
2021-02-16 2020-12-31 13F MERCK COM 58933Y105 61,351 -73,878 -54.63 5,019 -55.26 0.5814
2020-11-13 2020-09-30 13F MERCK COM 58933Y105 135,229 30,157 28.70 11,217 38.06 1.5425
2020-08-13 2020-06-30 13F MERCK COM 58933Y105 105,072 -32,331 -23.53 8,125 -23.15 1.2117
2020-05-13 2020-03-31 13F MERCK COM 58933Y105 137,403 -32,303 -19.03 10,572 -31.51 1.9955
2020-02-13 2019-12-31 13F MERCK COM 58933Y105 169,706 19,078 12.67 15,435 21.73 1.9740
2019-11-13 2019-09-30 13F MERCK COM 58933Y105 150,628 15,018 11.07 12,680 11.51 1.7744
2019-08-13 2019-06-30 13F MERCK COM 58933Y105 135,610 -17,170 -11.24 11,371 -10.51 1.5012
2019-05-14 2019-03-31 13F MERCK & COM 58933Y105 152,780 -4,051 -2.58 12,707 6.04 1.7090
2019-02-14 2018-12-31 13F MERCK COM 58933Y105 156,831 1,916 1.24 11,983 9.04 2.2493
2018-11-14 2018-09-30 13F MERCK COM 58933Y105 154,915 94,017 154.38 10,990 197.27 1.4235
2018-08-13 2018-06-30 13F MERCK COM 58933Y105 60,898 1,399 2.35 3,697 14.07 0.6223
2018-05-14 2018-03-31 13F MERCK COM 58933Y105 59,499 19,021 46.99 3,241 42.27 0.6177
2018-02-14 2017-12-31 13F MERCK COM 58933Y105 40,478 -4,616 -10.24 2,278 -21.09 0.3491
2017-11-14 2017-09-30 13F MERCK COM 58933Y105 45,094 -83 -0.18 2,887 -0.28 0.4831
2017-08-14 2017-06-30 13F MERCK COM 58933Y105 45,177 244 0.54 2,895 1.40 0.5084
2017-05-12 2017-03-31 13F MERCK COM 58933Y105 44,933 -1,200 -2.60 2,855 5.12 0.5445
2017-02-15 2016-12-31 13F MERCK & CO INC COM 58933Y105 46,133 -4,569 -9.01 2,716 -14.16 0.6165
2016-11-14 2016-09-30 13F MERCK & CO INC COM 58933Y105 50,702 -134,180 -72.58 3,164 -70.29 0.8744
2016-08-15 2016-06-30 13F MERCK & CO INC COM 58933Y105 184,882 184,882 0.00 10,651 2.4191
2016-05-13 2016-03-31 13F MERCK & CO INC COM 58933Y105 0 -133,236 -100.00 0 -100.00
2016-02-10 2015-12-31 13F MERCK & CO INC COM 58933Y105 133,236 4,383 3.40 7,038 10.59 1.7632
2015-11-13 2015-09-30 13F MERCK & CO INC COM 58933Y105 128,853 13,493 11.70 6,364 -3.09 1.8506
2015-07-21 2015-06-30 13F MERCK & CO INC COM 58933Y105 115,360 5,021 4.55 6,567 3.55 1.6715
2015-05-14 2015-03-31 13F MERCK & CO INC COM 58933Y105 110,339 5,772 5.52 6,342 6.80 1.6704
2015-03-09 2014-12-31 13F/A-1 MERCK & CO INC COM 58933Y105 104,567 24,130 30.00 5,938 24.54 1.8593
2015-02-17 2014-12-31 13F MERCK & CO INC COM 58933Y105 104,567 5,938
2015-03-09 2014-09-30 13F/A-1 MERCK & CO INC NEW COM COM 58933Y105 80,437 -28,745 -26.33 4,768 -24.51 2.3354
2014-11-14 2014-09-30 13F MERCK & CO INC NEW COM COM 58933Y105 80,437 4,768
2014-08-20 2014-06-30 13F/A-2 MERCK & CO INC NEW COM COM 58933Y105 109,182 23,263 6,316 2.5153
2015-03-09 2014-06-30 13F/A-3 MERCK & CO INC NEW COM COM 58933Y105 109,182 23,263 27.08 6,316 29.48 2.5153
2014-05-15 2014-03-31 13F MERCK & CO INC NEW COM COM 58933Y105 85,919 85,919 782.49 4,878 951.29 2.6023
2014-02-11 2013-12-31 13F MERCK & CO INC NEW COM COM 58933Y105 0 -9,736 -100.00 0 -100.00
2013-11-12 2013-09-30 13F MERCK & CO INC NEW COM COM 58933Y105 9,736 -106,994 -91.66 464 -91.44 0.1879
2013-08-14 2013-06-30 13F MERCK & CO INC NEW COM COM 58933Y105 116,730 116,730 5,422 2.6486
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.