Merck & Co., Inc.
MX ˙ BMV ˙ US58933Y1055
SecurityMX:MRK / Merck & Co., Inc.
InstitutionProfessional Advisory Services Inc
Latest Disclosed Ownership7,972 shares
Latest Disclosed Value $ 959
Professional Advisory Services Inc ownership in MRK / Merck & Co., Inc.

On April 15, 2026 - Professional Advisory Services Inc filed a 13F-HR form disclosing ownership of 7,972 shares of Merck & Co., Inc. (MX:MRK) valued at $959 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 12, 2026 disclosing 7,972 shares of Merck & Co., Inc..

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)
2026-04-15 2026-03-31 13F MERCK COM 58933Y105 7,972 0 0.00 1 0.1324
2026-01-12 2025-12-31 13F MERCK COM 58933Y105 7,972 0 0.00 1 0.1087
2025-10-29 2025-09-30 13F MERCK COM 58933Y105 7,972 0 0.00 1 0.0871
2025-07-11 2025-06-30 13F MERCK COM 58933Y105 7,972 -794 -9.06 1 0.0856
2025-04-14 2025-03-31 13F MERCK COM 58933Y105 8,766 294 3.47 1 0.1102
2025-01-15 2024-12-31 13F MERCK COM 58933Y105 8,472 0 0.00 1 0.1163
2024-10-17 2024-09-30 13F MERCK COM 58933Y105 8,472 0 0.00 1 -100.00 0.1263
2024-07-10 2024-06-30 13F MERCK COM 58933Y105 8,472 -130 -1.51 1 0.00 0.1432
2024-04-22 2024-03-31 13F MERCK COM 58933Y105 8,602 130 1.53 1 0.1540
2024-01-10 2023-12-31 13F MERCK COM 58933Y105 8,472 150 1.80 1 0.1320
2023-10-10 2023-09-30 13F MERCK COM 58933Y105 8,322 0 0.00 1 0.1410
2023-07-10 2023-06-30 13F MERCK COM 58933Y105 8,322 -130 -1.54 1 0.1457
2023-04-11 2023-03-31 13F MERCK COM 58933Y105 8,452 130 1.56 1 0.1401
2023-01-13 2022-12-31 13F MERCK COM 58933Y105 8,322 0 0.00 1 -100.00 0.1502
2022-10-11 2022-09-30 13F MERCK COM 58933Y105 8,322 0 0.00 717 -5.53 0.1245
2022-07-13 2022-06-30 13F MERCK COM 58933Y105 8,322 1,000 13.66 759 26.29 0.1265
2022-04-18 2022-03-31 13F MERCK COM 58933Y105 7,322 0 0.00 601 7.13 0.0863
2022-01-19 2021-12-31 13F MERCK COM 58933Y105 7,322 0 0.00 561 2.00 0.0763
2021-10-05 2021-09-30 13F MERCK COM 58933Y105 7,322 0 0.00 550 -3.34 0.0808
2021-08-20 2021-06-30 13F MERCK COM 58933Y105 7,322 0 0.00 569 0.89 0.0826
2021-04-26 2021-03-31 13F MERCK COM 58933Y105 7,322 0 0.00 564 -5.84 0.0864
2021-01-21 2020-12-31 13F MERCK COM 58933Y105 7,322 0 0.00 599 -1.32 0.0963
2020-10-19 2020-09-30 13F MERCK COM 58933Y105 7,322 100 1.38 607 8.78 0.1084
2020-07-24 2020-06-30 13F MERCK COM 58933Y105 7,222 0 0.00 558 0.36 0.1074
2020-04-23 2020-03-31 13F MERCK COM 58933Y105 7,222 0 0.00 556 -15.37 0.1290
2020-01-23 2019-12-31 13F MERCK COM 58933Y105 7,222 0 0.00 657 8.06 0.1170
2019-10-28 2019-09-30 13F MERCK COM 58933Y105 7,222 0 0.00 608 0.33 0.1156
2019-07-30 2019-06-30 13F MERCK COM 58933Y105 7,222 0 0.00 606 0.83 0.1175
2019-04-29 2019-03-31 13F MERCK COM 58933Y105 7,222 0 0.00 601 8.88 0.1207
2019-01-17 2018-12-31 13F MERCK COM 58933Y105 7,222 0 0.00 552 7.81 0.1230
2018-10-25 2018-09-30 13F MERCK COM 58933Y105 7,222 -150 -2.03 512 14.54 0.1010
2018-07-25 2018-06-30 13F MERCK COM 58933Y105 7,372 0 0.00 447 11.19 0.0922
2018-04-24 2018-03-31 13F MERCK COM 58933Y105 7,372 0 0.00 402 -3.13 0.0870
2018-01-19 2017-12-31 13F MERCK COM 58933Y105 7,372 0 0.00 415 -12.08 0.0875
2017-10-12 2017-09-30 13F MERCK COM 58933Y105 7,372 0 0.00 472 0.00 0.1006
2017-07-13 2017-06-30 13F MERCK COM 58933Y105 7,372 0 0.00 472 0.85 0.1024
2017-04-19 2017-03-31 13F MERCK COM 58933Y105 7,372 0 0.00 468 7.83 0.1036
2017-01-19 2016-12-31 13F MERCK COM 58933Y105 7,372 0 0.00 434 -5.65 0.1009
2016-10-20 2016-09-30 13F MERCK COM 58933Y105 7,372 150 2.08 460 10.58 0.1049
2016-07-15 2016-06-30 13F MERCK COM 58933Y105 7,222 0 0.00 416 8.90 0.0952
2016-04-15 2016-03-31 13F MERCK COM 58933Y105 7,222 0 0.00 382 0.26 0.0903
2016-01-19 2015-12-31 13F MERCK COM 58933Y105 7,222 0 0.00 381 6.72 0.0909
2015-10-26 2015-09-30 13F MERCK COM 58933Y105 7,222 0 0.00 357 -13.14 0.0896
2015-07-15 2015-06-30 13F MERCK COM 58933Y105 7,222 0 0.00 411 -0.96 0.0985
2015-04-20 2015-03-31 13F MERCK COM 58933Y105 7,222 0 0.00 415 1.22 0.0997
2015-01-22 2014-12-31 13F MERCK COM 58933Y105 7,222 0 0.00 410 -4.21 0.0956
2014-10-21 2014-09-30 13F MERCK COM 58933Y105 7,222 0 0.00 428 2.39 0.1035
2014-07-23 2014-06-30 13F MERCK COM 58933Y105 7,222 0 0.00 418 1.95 0.1015
2014-04-08 2014-03-31 13F MERCK COM 58933Y105 7,222 0 0.00 410 13.57 0.1023
2014-02-10 2013-12-31 13F MERCK COM 58933Y105 7,222 0 0.00 361 4.94 0.0938
2013-10-18 2013-09-30 13F MERCK COM 58933Y105 7,222 0 0.00 344 2.08 0.0970
2013-07-29 2013-06-30 13F MERCK COM 58933Y105 7,222 7,222 337 0.1007
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.