Merck & Co., Inc.
DE ˙ XTRA ˙ US58933Y1055
102,78 € ↑2,84 (2,84%)
2026-06-04
PREZZO DELLE AZIONI
SecurityDE:6MK / Merck & Co., Inc.
InstitutionMorgan Stanley
Latest Disclosed Ownership47,632,487 shares
Latest Disclosed Value $ 5,729,712,158
Morgan Stanley reports 5.98% increase in ownership of 6MK / Merck & Co., Inc.

On May 15, 2026 - Morgan Stanley filed a 13F-HR form disclosing ownership of 47,632,487 shares of Merck & Co., Inc. (DE:6MK) valued at $4,963,305,145 USD as of March 31, 2026. The entity filed a previous 13F-HR/A on May 27, 2026 disclosing 44,946,021 shares of Merck & Co., Inc.. This represents a change in shares of 5.98% during the quarter. The current value of the position is $4,895,667,014 USD.

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 47,632,487 2,686,466 5.98 5,729,712 21.11 0.3452
2026-05-27 2025-12-31 13F/A-1 MERCK COM 58933Y105 44,946,021 359,486 0.81 4,731,018 26.43 0.2825
2026-02-13 2025-12-31 13F MERCK COM 58933Y105 44,946,021 359,486 4,731,018 0.2824
2026-05-27 2025-09-30 13F/A-1 MERCK COM 58933Y105 44,586,535 385,841 0.87 3,742,148 6.95 0.2266
2025-11-14 2025-09-30 13F MERCK COM 58933Y105 44,586,535 385,841 3,742,148 0.2266
2025-08-15 2025-06-30 13F MERCK COM 58933Y105 44,200,694 1,086,242 2.52 3,498,927 -9.59 0.2279
2025-05-15 2025-03-31 13F MERCK COM 58933Y105 43,114,452 -1,069,247 -2.42 3,869,953 -11.95 0.2767
2025-05-15 2024-12-31 13F/A-1 MERCK COM 58933Y105 44,183,699 -208,123 -0.47 4,395,395 -12.81 0.3080
2025-02-14 2024-12-31 13F MERCK COM 58933Y105 44,183,699 -208,123 4,395,395 0.3079
2025-05-14 2024-09-30 13F/A-2 MERCK COM 58933Y105 44,391,822 2,174,461 5.15 5,041,136 -3.55 0.3655
2025-02-14 2024-09-30 13F/A-1 MERCK COM 58933Y105 44,391,822 2,174,461 5,041,136 0.3655
2024-11-14 2024-09-30 13F MERCK COM 58933Y105 44,391,822 2,174,461 5,041,136 0.3655
2025-05-14 2024-06-30 13F/A-2 MERCK COM 58933Y105 42,217,361 711,506 1.71 5,226,510 -4.57 0.4044
2024-10-17 2024-06-30 13F/A-1 MERCK COM 58933Y105 42,217,361 711,506 5,226,510 0.4044
2024-08-14 2024-06-30 13F MERCK COM 58933Y105 42,217,361 711,506 5,226,510 0.4044
2024-10-17 2024-03-31 13F/A-2 MERCK COM 58933Y105 41,505,855 1,376,030 3.43 5,476,698 25.18 0.4394
2024-08-16 2024-03-31 13F/A-1 MERCK COM 58933Y105 41,505,855 1,376,030 5,476,698 0.4395
2024-05-15 2024-03-31 13F MERCK COM 58933Y105 41,505,855 1,376,030 5,476,698 0.4395
2024-08-16 2023-12-31 13F/A-1 MERCK COM 58933Y105 40,129,825 1,535,032 3.98 4,374,954 10.11 0.3855
2024-02-13 2023-12-31 13F MERCK COM 58933Y105 40,129,825 1,535,032 4,374,954 0.3855
2023-11-15 2023-09-30 13F MERCK COM 58933Y105 38,594,793 -572,824 -1.46 3,973,334 -12.09 0.4040
2023-08-14 2023-06-30 13F MERCK COM 58933Y105 39,167,617 122,796 0.31 4,519,552 8.80 0.4454
2023-05-15 2023-03-31 13F MERCK COM 58933Y105 39,044,821 -2,805,260 -6.70 4,153,979 -10.54 0.4454
2023-02-14 2022-12-31 13F MERCK COM 58933Y105 41,850,081 4,000,816 10.57 4,643,267 42.45 0.5274
2022-11-14 2022-09-30 13F MERCK COM 58933Y105 37,849,265 -126,218 -0.33 3,259,579 -5.85 0.4443
2022-10-27 2022-06-30 13F/A-1 MERCK COM 58933Y105 37,975,483 12,483,322 48.97 3,462,228 65.53 0.4494
2022-08-15 2022-06-30 13F MERCK COM 58933Y105 37,975,483 12,483,322 3,462,228 0.4494
2022-10-27 2022-03-31 13F/A-1 MERCK COM 58933Y105 25,492,161 -3,932,782 -13.37 2,091,629 -7.25 0.2821
2022-05-13 2022-03-31 13F MERCK COM 58933Y105 25,492,161 -3,932,782 2,091,629 0.2821
2022-02-14 2021-12-31 13F MERCK COM 58933Y105 29,424,943 3,287,041 12.58 2,255,128 14.87 0.2785
2021-11-15 2021-09-30 13F MERCK COM 58933Y105 26,137,902 -151,594 -0.58 1,963,218 -3.98 0.2644
2021-08-23 2021-06-30 13F/A-1 MERCK COM 58933Y105 26,289,496 3,832,086 17.06 2,044,534 18.10 0.2697
2021-08-16 2021-06-30 13F MERCK COM 58933Y105 26,289,496 3,832,086 2,044,534 0.0561
2021-05-17 2021-03-31 13F MERCK & CO. COM 58933Y105 22,457,410 -111,956 -0.50 1,731,241 -6.23 0.2543
2021-02-16 2020-12-31 13F MERCK & CO. COM 58933Y105 22,569,366 3,221,509 16.65 1,846,174 15.03 0.2851
2020-11-13 2020-09-30 13F MERCK & CO. COM 58933Y105 19,347,857 653,675 3.50 1,604,905 11.02 0.3104
2020-08-14 2020-06-30 13F MERCK & CO. COM 58933Y105 18,694,182 762,081 4.25 1,445,621 4.78 0.3200
2020-05-26 2020-03-31 13F/A-1 MERCK & CO. COM 58933Y105 17,932,101 -515,303 -2.79 1,379,697 -17.77 0.3749
2020-05-15 2020-03-31 13F MERCK & CO. COM 58933Y105 17,932,101 -515,303 1,379,697 105,989.4914
2020-02-14 2019-12-31 13F MERCK COM 58933Y105 18,447,404 1,447,644 8.52 1,677,791 17.24 0.3902
2019-11-14 2019-09-30 13F MERCK COM 58933Y105 16,999,760 938,593 5.84 1,431,040 6.26 0.3788
2019-08-14 2019-06-30 13F MERCK COM 58933Y105 16,061,167 158,002 0.99 1,346,729 1.82 0.3584
2019-05-15 2019-03-31 13F MERCK COM 58933Y105 15,903,165 -4,136,334 -20.64 1,322,664 -13.62 0.3744
2019-02-14 2018-12-31 13F MERCK COM 58933Y105 20,039,499 3,472,498 20.96 1,531,216 30.29 0.4582
2019-04-23 2018-09-30 13F/A-2 MERCK COM 58933Y105 16,567,001 661,167 4.16 1,175,261 21.73 0.2942
2018-11-20 2018-09-30 13F/A-1 MERCK COM 58933Y105 16,567,001 0 1,175,261 0.2942
2018-11-14 2018-09-30 13F MERCK COM 58933Y105 16,567,001 661,167 1,175,261
2019-04-23 2018-06-30 13F/A-1 MERCK COM 58933Y105 15,905,834 149,438 0.95 965,485 12.49 0.2608
2018-08-14 2018-06-30 13F MERCK COM 58933Y105 15,905,834 149,438 965,485
2019-04-23 2018-03-31 13F/A-1 MERCK COM 58933Y105 15,756,396 1,374,803 9.56 858,248 6.05 0.2382
2018-05-14 2018-03-31 13F MERCK COM 58933Y105 15,756,396 1,374,803 858,248
2019-04-23 2017-12-31 13F/A-1 MERCK COM 58933Y105 14,381,593 -591,339 -3.95 809,251 -15.59 0.2215
2018-02-14 2017-12-31 13F MERCK COM 58933Y105 14,381,593 -591,339 809,251
2017-11-14 2017-09-30 13F MERCK COM 58933Y105 14,972,932 323,120 2.21 958,716 2.11 0.2872
2017-08-11 2017-06-30 13F MERCK COM 58933Y105 14,649,812 -520,173 -3.43 938,905 -2.59 0.2837
2017-05-22 2017-03-31 13F/A-1 MERCK COM 58933Y105 15,169,985 -420,939 -2.70 963,901 5.02 0.2963
2017-05-12 2017-03-31 13F MERCK COM 58933Y105 15,169,985 963,901
2017-02-22 2016-12-31 13F/A-1 MERCK COM 58933Y105 15,590,924 2,843,209 22.30 917,838 15.37 0.3004
2017-02-13 2016-12-31 13F MERCK COM 58933Y105 15,590,924 917,838
2016-11-10 2016-09-30 13F MERCK COM 58933Y105 12,747,715 -2,025,434 -13.71 795,584 -6.52 0.2717
2016-08-12 2016-06-30 13F MERCK COM 58933Y105 14,773,149 3,355,548 29.39 851,080 40.88 0.3074
2016-05-12 2016-03-31 13F MERCK & CO INC COM 58933Y105 11,417,601 -1,334,469 -10.46 604,104 -10.31 0.2325
2016-02-09 2015-12-31 13F MERCK & CO INC COM 58933Y105 12,752,070 850,146 7.14 673,563 14.58 0.2438
2016-02-08 2015-09-30 13F/A-1 MERCK & CO INC COM 58933Y105 11,901,924 170,560 1.45 587,835 -11.98 0.2172
2015-11-09 2015-09-30 13F MERCK & CO INC COM 58933Y105 11,901,924 587,835
2015-08-12 2015-06-30 13F MERCK & CO INC COM 58933Y105 11,731,364 909,723 8.41 667,867 7.37 0.2315
2015-05-14 2015-03-31 13F MERCK & CO INC COM 58933Y105 10,821,641 -2,013,992 -15.69 622,027 -14.67 0.2291
2015-02-13 2014-12-31 13F MERCK & CO INC COM 58933Y105 12,835,633 1,693,338 15.20 728,934 10.36 0.2666
2014-12-16 2014-09-30 13F/A-1 MERCK & CO INC COM 58933Y105 11,142,295 1,353,250 13.82 660,514 18.86 0.2540
2014-11-14 2014-09-30 13F MERCK & CO INC COM 58933Y105 11,142,295 660,514
2014-05-13 2014-03-31 13F MERCK & CO INC COM 58933Y105 9,789,045 348,112 3.69 555,724 17.61 0.2327
2014-02-13 2013-12-31 13F MERCK & CO INC COM 58933Y105 9,440,933 -37,130 -0.39 472,518 4.72 0.2010
2013-11-13 2013-09-30 13F MERCK COM 58933Y105 9,478,063 -75,345 -0.79 451,240 1.69 0.2133
2013-08-08 2013-06-30 13F MERCK COM 58933Y105 9,553,408 9,553,408 443,756 0.2238
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.