Merck & Co., Inc.
MX ˙ BMV ˙ US58933Y1055
SecurityMX:MRK / Merck & Co., Inc.
InstitutionFayez Sarofim & Co
Latest Disclosed Ownership1,700,379 shares
Latest Disclosed Value $ 204,538,582
Fayez Sarofim & Co reports 2.27% decrease in ownership of MRK / Merck & Co., Inc.

On May 15, 2026 - Fayez Sarofim & Co filed a 13F-HR form disclosing ownership of 1,700,379 shares of Merck & Co., Inc. (MX:MRK) valued at $204,538,582 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 1,739,889 shares of Merck & Co., Inc.. This represents a change in shares of -2.27% 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 Common Stock 58933Y105 1,700,379 -39,510 -2.27 204,539 11.68 0.1658
2026-02-13 2025-12-31 13F MERCK Common Stock 58933Y105 1,739,889 -666,433 -27.70 183,141 -9.32 0.4396
2025-11-14 2025-09-30 13F MERCK & CO INC COM COM 58933Y105 2,406,322 -214,403 -8.18 201,963 -2.65 0.4684
2025-08-14 2025-06-30 13F MERCK COM 58933Y105 2,620,725 -296,666 -10.17 207,457 -20.78 0.4978
2025-05-12 2025-03-31 13F MERCK COM 58933Y105 2,917,391 -287,516 -8.97 261,865 -17.87 0.6512
2025-02-14 2024-12-31 13F MERCK COM 58933Y105 3,204,907 309,716 10.70 318,824 -3.03 0.7749
2024-11-14 2024-09-30 13F MERCK COM 58933Y105 2,895,191 -26,749 -0.92 328,778 -9.11 0.8358
2024-08-14 2024-06-30 13F MERCK COM 58933Y105 2,921,940 718,344 32.60 361,736 24.41 0.9761
2024-05-14 2024-03-31 13F MERCK COM 58933Y105 2,203,596 -209,455 -8.68 290,765 -3.95 0.8666
2024-02-15 2023-12-31 13F MERCK&COINC COM 58933Y105 2,413,051 -50,206 -2.04 302,717 19.37 0.9251
2023-11-15 2023-09-30 13F MERCK COM 58933Y105 2,463,257 67,646 2.82 253,592 -8.26 0.8557
2023-08-14 2023-06-30 13F MERCK COM 58933Y105 2,395,611 -904,765 -27.41 276,430 -21.27 0.9681
2023-05-11 2023-03-31 13F MERCK COM 58933Y105 3,300,376 -131,058 -3.82 351,127 -7.77 1.2289
2023-02-13 2022-12-31 13F MERCK COM 58933Y105 3,431,434 -31,423 -0.91 380,718 27.66 1.4066
2022-11-15 2022-09-30 13F MERCK COM 58933Y105 3,462,857 -679 -0.02 298,222 -5.56 1.1782
2022-08-12 2022-06-30 13F MERCK COM 58933Y105 3,463,536 3,602 0.10 315,770 11.23 1.1532
2022-05-16 2022-03-31 13F MERCK COM 58933Y105 3,459,934 1,409 0.04 283,888 7.10 0.8982
2022-02-11 2021-12-31 13F MERCK COM 58933Y105 3,458,525 48,504 1.42 265,061 3.49 0.7946
2021-11-15 2021-09-30 13F MERCK COM 58933Y105 3,410,021 -3,177 -0.09 256,128 -3.51 0.8472
2021-08-13 2021-06-30 13F Merck&CoInc COMMON 58933Y105 3,413,198 -10,314 -0.30 265,444 0.58 0.8906
2021-05-13 2021-03-31 13F Merck&CoInc COMMON 58933Y105 3,423,512 102,089 3.07 263,919 -2.86 0.9704
2021-02-11 2020-12-31 13F Merck&CoInc COMMON 58933Y105 3,321,423 57,096 1.75 271,692 0.34 1.0434
2020-11-13 2020-09-30 13F Merck&CoInc COMMON 58933Y105 3,264,327 23,740 0.73 270,776 8.05 1.1604
2020-08-11 2020-06-30 13F Merck&CoInc COMMON 58933Y105 3,240,587 4,873 0.15 250,595 0.66 1.1557
2020-05-12 2020-03-31 13F Merck&CoInc COMMON 58933Y105 3,235,714 102,026 3.26 248,955 -12.65 1.5299
2020-02-14 2019-12-31 13F Merck&CoInc COMMON 58933Y105 3,133,688 28,016 0.90 285,009 9.02 1.3728
2019-11-13 2019-09-30 13F Merck&CoInc COMMON 58933Y105 3,105,672 23,044 0.75 261,436 1.14 1.3477
2019-08-09 2019-06-30 13F Merck&CoInc COMMON 58933Y105 3,082,628 84,446 2.82 258,478 3.66 1.3366
2019-05-14 2019-03-31 13F Merck&CoInc COMMON 58933Y105 2,998,182 20,886 0.70 249,359 9.61 1.3155
2019-02-13 2018-12-31 13F Merck&CoInc COMMON 58933Y105 2,977,296 47,467 1.62 227,496 9.46 1.3710
2018-11-14 2018-09-30 13F Merck&CoInc COMMON 58933Y105 2,929,829 9,835 0.34 207,842 17.26 1.0854
2018-08-14 2018-06-30 13F Merck&CoInc COMMON 58933Y105 2,919,994 46,608 1.62 177,244 13.24 0.9540
2018-05-10 2018-03-31 13F Merck&CoInc COMMON 58933Y105 2,873,386 -46,534 -1.59 156,514 -4.74 0.8480
2018-02-13 2017-12-31 13F Merck&CoInc COMMON 58933Y105 2,919,920 -57,118 -1.92 164,305 -13.80 0.8514
2017-11-08 2017-09-30 13F Merck&CoInc COMMON 58933Y105 2,977,038 2,741 0.09 190,620 0.00 1.0021
2017-08-11 2017-06-30 13F Merck&CoInc COMMON 58933Y105 2,974,297 -28,275 -0.94 190,622 -0.08 1.0179
2017-05-12 2017-03-31 13F Merck&CoInc COMMON 58933Y105 3,002,572 -92,265 -2.98 190,783 4.71 1.0389
2017-02-14 2016-12-31 13F Merck&CoInc COMMON 58933Y105 3,094,837 -45,828 -1.46 182,193 -7.05 1.0009
2016-11-21 2016-09-30 13F/A-1 Merck&CoInc COMMON 58933Y105 3,140,665 -19,071 -0.60 196,009 7.68 1.0667
2016-11-14 2016-09-30 13F Merck&CoInc COMMON 58933Y105 3,140,665 196,009
2016-08-10 2016-06-30 13F Merck&CoInc COMMON 58933Y105 3,159,736 9,786 0.31 182,033 9.22 0.9972
2016-05-13 2016-03-31 13F Merck&CoInc COMMON 58933Y105 3,149,950 -38,005 -1.19 166,664 -1.02 0.9553
2016-02-12 2015-12-31 13F Merck&CoInc COMMON 58933Y105 3,187,955 -92,212 -2.81 168,388 3.94 0.9694
2015-11-12 2015-09-30 13F Merck&CoInc COMMON 58933Y105 3,280,167 -169,507 -4.91 162,007 -17.51 0.9357
2015-08-13 2015-06-30 13F Merck&CoInc COMMON 58933Y105 3,449,674 -166,351 -4.60 196,390 -5.51 0.9995
2015-05-12 2015-03-31 13F Merck&CoInc COMMON 58933Y105 3,616,025 -829,474 -18.66 207,849 -17.72 1.0192
2015-02-13 2014-12-31 13F Merck&CoInc COMMON 58933Y105 4,445,499 -401,376 -8.28 252,604 -12.02 1.1976
2014-11-14 2014-09-30 13F Merck&CoInc COMMON 58933Y105 4,846,875 -113,738 -2.29 287,114 -0.04 1.3409
2014-08-14 2014-06-30 13F Merck&CoInc COMMON 58933Y105 4,960,613 -123,345 -2.43 287,220 -0.43 1.3142
2014-05-14 2014-03-31 13F Merck&CoInc COMMON 58933Y105 5,083,958 -95,744 -1.85 288,459 11.27 1.3746
2014-02-14 2013-12-31 13F Merck&CoInc COMMON 58933Y105 5,179,702 -256,852 -4.72 259,243 2.66 1.2032
2013-08-13 2013-06-30 13F Merck&CoInc COMMON 58933Y105 5,436,554 5,436,554 252,528 1.2673
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.