Merck & Co., Inc.
MX ˙ BMV ˙ US58933Y1055
SecurityMX:MRK / Merck & Co., Inc.
InstitutionSumitomo Mitsui Trust Holdings, Inc.
Latest Disclosed Ownership6,269,316 shares
Latest Disclosed Value $ 754,136,022
Sumitomo Mitsui Trust Holdings, Inc. reports 10.08% decrease in ownership of MRK / Merck & Co., Inc.

On April 30, 2026 - Sumitomo Mitsui Trust Holdings, Inc. filed a 13F-HR form disclosing ownership of 6,269,316 shares of Merck & Co., Inc. (MX:MRK) valued at $754,136,022 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 23, 2026 disclosing 6,971,801 shares of Merck & Co., Inc.. This represents a change in shares of -10.08% 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)
2026-04-30 2026-03-31 13F MERCK COM 58933Y105 6,269,316 -702,485 -10.08 754,136 2.76 0.4882
2026-01-23 2025-12-31 13F MERCK COM 58933Y105 6,971,801 -394,387 -5.35 733,852 18.70 0.4310
2025-10-27 2025-09-30 13F MERCK COM 58933Y105 7,366,188 -70,408 -0.95 618,244 5.02 0.3557
2025-07-31 2025-06-30 13F MERCK COM 58933Y105 7,436,596 150,919 2.07 588,681 -9.98 0.3668
2025-04-25 2025-03-31 13F MERCK COM 58933Y105 7,285,677 72,944 1.01 653,962 -8.86 0.4623
2025-01-28 2024-12-31 13F MERCK COM 58933Y105 7,212,733 675,591 10.33 717,523 -3.35 0.4843
2024-11-05 2024-09-30 13F MERCK COM 58933Y105 6,537,142 43,578 0.67 742,358 -7.66 0.5145
2024-07-19 2024-06-30 13F MERCK COM 58933Y105 6,493,564 -576,723 -8.16 803,903 -13.83 0.5934
2024-04-19 2024-03-31 13F MERCK COM 58933Y105 7,070,287 296,092 4.37 932,924 26.32 0.6405
2024-01-30 2023-12-31 13F MERCK COM 58933Y105 6,774,195 -118,169 -1.71 738,523 4.08 0.5460
2023-10-30 2023-09-30 13F MERCK COM 58933Y105 6,892,364 -530,378 -7.15 709,569 -17.16 0.5826
2023-07-31 2023-06-30 13F MERCK COM 58933Y105 7,422,742 -958,591 -11.44 856,510 -3.95 0.6671
2023-04-27 2023-03-31 13F MERCK COM 58933Y105 8,381,333 64,359 0.77 891,690 -3.37 0.6644
2023-01-30 2022-12-31 13F MERCK COM 58933Y105 8,316,974 -157,337 -1.86 922,768 26.44 0.7306
2022-10-21 2022-09-30 13F MERCK COM 58933Y105 8,474,311 142,055 1.70 729,808 -3.93 0.5997
2022-07-26 2022-06-30 13F MERCK COM 58933Y105 8,332,256 411,778 5.20 759,652 16.89 0.5843
2022-04-27 2022-03-31 13F MERCK COM 58933Y105 7,920,478 58,941 0.75 649,875 7.86 0.4328
2022-02-02 2021-12-31 13F MERCK COM 58933Y105 7,861,537 -285,117 -3.50 602,508 -1.53 0.3663
2021-10-25 2021-09-30 13F MERCK COM 58933Y105 8,146,654 -598,336 -6.84 611,895 -10.03 0.3811
2021-08-02 2021-06-30 13F MERCK COM 58933Y105 8,744,990 -387,633 -4.24 680,098 -3.40 0.4021
2021-04-30 2021-03-31 13F MERCK COM 58933Y105 9,132,623 -183,416 -1.97 704,034 -7.61 0.4400
2021-02-05 2020-12-31 13F MERCK COM 58933Y105 9,316,039 -1,844,145 -16.52 762,052 -17.68 0.4923
2020-10-30 2020-09-30 13F MERCK COM 58933Y105 11,160,184 -1,438,306 -11.42 925,737 -4.98 0.6236
2020-07-27 2020-06-30 13F MERCK COM 58933Y105 12,598,490 892,849 7.63 974,241 8.17 0.6881
2020-04-27 2020-03-31 13F MERCK COM 58933Y105 11,705,641 930,272 8.63 900,632 -8.10 0.7744
2020-01-31 2019-12-31 13F MERCK COM 58933Y105 10,775,369 -71,224 -0.66 980,020 7.33 0.7704
2019-10-31 2019-09-30 13F MERCK COM 58933Y105 10,846,593 338,355 3.22 913,066 3.63 0.7932
2019-07-29 2019-06-30 13F MERCK COM 58933Y105 10,508,238 127,619 1.23 881,116 2.06 0.7866
2019-05-08 2019-03-31 13F MERCK COM 58933Y105 10,380,619 -110,516 -1.05 863,356 9.19 0.7985
2019-02-06 2018-12-31 13F MERCK COM 58933Y105 10,491,135 1,617,670 18.23 790,717 25.61 0.8503
2018-11-07 2018-09-30 13F MERCK COM 58933Y105 8,873,465 130,994 1.50 629,484 18.62 0.6767
2018-08-01 2018-06-30 13F MERCK COM 58933Y105 8,742,471 479,302 5.80 530,668 17.90 0.6185
2018-05-01 2018-03-31 13F MERCK COM 58933Y105 8,263,169 151,723 1.87 450,095 -1.39 0.5788
2018-02-06 2017-12-31 13F MERCK COM 58933Y105 8,111,446 130,172 1.63 456,431 -10.69 0.5892
2017-11-07 2017-09-30 13F MERCK COM 58933Y105 7,981,274 -115,438 -1.43 511,041 -1.52 0.7212
2017-08-07 2017-06-30 13F MERCK COM 58933Y105 8,096,712 158,794 2.00 518,918 2.88 0.7613
2017-05-02 2017-03-31 13F MERCK COM 58933Y105 7,937,918 46,053 0.58 504,375 8.56 0.7793
2017-01-27 2016-12-31 13F MERCK COM 58933Y105 7,891,865 -207,850 -2.57 464,594 -8.09 0.7582
2016-10-28 2016-09-30 13F MERCK COM 58933Y105 8,099,715 120,129 1.51 505,503 9.96 0.8290
2016-07-29 2016-06-30 13F MERCK COM 58933Y105 7,979,586 -1,365 -0.02 459,704 8.86 0.7918
2016-05-06 2016-03-31 13F MERCK COM 58933Y105 7,980,951 -180,645 -2.21 422,272 -2.84 0.7386
2016-02-09 2015-12-31 13F MERCK COM 58933Y105 8,161,596 -246,066 -2.93 434,605 4.66 0.7770
2015-11-06 2015-09-30 13F MERCK COM 58933Y105 8,407,662 534,734 6.79 415,254 -7.35 0.8039
2015-07-31 2015-06-30 13F Merck COM 58933Y105 7,872,928 128,424 1.66 448,206 0.69 0.8053
2015-05-08 2015-03-31 13F Merck COM 58933Y105 7,744,504 7,744,504 0.00 445,154 0.8034
2015-02-04 2014-12-31 13F Merck COM 58933Y105 0 -7,183,440 -100.00 0 -100.00
2014-11-07 2014-09-30 13F Merck COM 58933Y105 7,183,440 -46,437 -0.64 425,834 1.81 0.8536
2014-08-11 2014-06-30 13F Merck COM 58933Y105 7,229,877 -217,874 -2.93 418,248 -1.08 0.8587
2014-05-09 2014-03-31 13F Merck COM 58933Y105 7,447,751 -738,177 -9.02 422,809 3.43 0.8897
2014-02-14 2013-12-31 13F Merck COM 58933Y105 8,185,928 -304,210 -3.58 408,805 1.14 0.8487
2013-11-07 2013-09-30 13F Merck COM 58933Y105 8,490,138 -24,217 -0.28 404,207 2.20 0.8739
2013-08-12 2013-06-30 13F Merck COM 58933Y105 8,514,355 8,514,355 395,492 0.8977
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.