Merck & Co., Inc.
BG ˙ BUL ˙ US58933Y1055
SecurityBG:6MK / Merck & Co., Inc.
InstitutionPrudential Plc
Latest Disclosed Ownership332,437 shares
Latest Disclosed Value $ 39,988,847
Prudential Plc reports 12.63% decrease in ownership of 6MK / Merck & Co., Inc.

On May 14, 2026 - Prudential Plc filed a 13F-HR form disclosing ownership of 332,437 shares of Merck & Co., Inc. (BG:6MK) valued at $39,988,847 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 11, 2026 disclosing 380,476 shares of Merck & Co., Inc.. This represents a change in shares of -12.63% 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)
2026-05-14 2026-03-31 13F MERCK COM 58933Y105 332,437 -48,039 -12.63 39,989 -0.15 0.1725
2026-02-11 2025-12-31 13F MERCK COM 58933Y105 380,476 -29,087 -7.10 40,049 16.51 0.3176
2025-11-14 2025-09-30 13F MERCK COM 58933Y105 409,563 11,393 2.86 34,375 9.06 0.2526
2025-08-12 2025-06-30 13F MERCK COM 58933Y105 398,170 56,360 16.49 31,519 2.73 0.1900
2025-05-13 2025-03-31 13F MERCK COM 58933Y105 341,810 31,758 10.24 30,681 -0.53 0.1536
2025-02-13 2024-12-31 13F MERCK COM 58933Y105 310,052 -73,375 -19.14 30,844 -29.16 0.1551
2024-11-13 2024-09-30 13F MERCK COM 58933Y105 383,427 1,327 0.35 43,542 -7.95 0.2187
2024-08-07 2024-06-30 13F MERCK COM 58933Y105 382,100 90,634 31.10 47,304 23.00 0.3190
2024-05-14 2024-03-31 13F MERCK COM 58933Y105 291,466 47,672 19.55 38,459 44.70 0.2931
2024-02-14 2023-12-31 13F MERCK COM 58933Y105 243,794 -24,444 -9.11 26,578 -3.76 0.2696
2023-11-13 2023-09-30 13F MERCK COM 58933Y105 268,238 -79,301 -22.82 27,615 -31.14 0.3069
2023-08-14 2023-06-30 13F MERCK COM 58933Y105 347,539 -20,129 -5.47 40,103 2.52 0.4689
2023-05-12 2023-03-31 13F MERCK COM 58933Y105 367,668 -19,267 -4.98 39,116 -8.88 0.4591
2023-02-09 2022-12-31 13F MERCK COM 58933Y105 386,935 62,895 19.41 42,930 53.84 0.5389
2022-11-14 2022-09-30 13F MERCK COM 58933Y105 324,040 104,515 47.61 27,906 39.43 0.4416
2022-08-12 2022-06-30 13F MERCK COM 58933Y105 219,525 12,357 5.96 20,014 17.74 0.3623
2022-05-13 2022-03-31 13F MERCK COM 58933Y105 207,168 -14,948 -6.73 16,998 -0.15 0.2458
2022-02-11 2021-12-31 13F MERCK COM 58933Y105 222,116 93,890 73.22 17,023 76.75 0.2330
2021-11-10 2021-09-30 13F MERCK COM 58933Y105 128,226 -227,225 -63.93 9,631 -65.16 0.1343
2021-08-13 2021-06-30 13F Merck Merck & Co Inc 58933Y105 355,451 -573,713 -61.75 27,643 -61.41 0.2562
2021-05-14 2021-03-31 13F Merck Merck & Co Inc 58933Y105 929,164 74,711 8.74 71,629 2.48 0.4963
2021-02-10 2020-12-31 13F/A-1 Merck Merck & Co Inc 58933Y105 854,453 -414,863 -32.68 69,894 -33.62 0.3712
2021-02-08 2020-12-31 13F Merck Merck & Co Inc 58933Y105 854,453 -414,863 69,895 159,035.3079
2020-10-30 2020-09-30 13F Merck Merck & Co Inc 58933Y105 1,269,316 -65,688 -4.92 105,291 1.99 0.5243
2020-07-31 2020-06-30 13F Merck Merck & Co Inc 58933Y105 1,335,004 -424,329 -24.12 103,236 -23.73 0.4971
2020-05-01 2020-03-31 13F Merck Merck & Co Inc 58933Y105 1,759,333 -618,319 -26.01 135,363 -37.40 0.7216
2020-02-13 2019-12-31 13F Merck Merck & Co Inc 58933Y105 2,377,652 -408,900 -14.67 216,247 -7.78 0.9116
2019-11-12 2019-09-30 13F MERCK COM 58933Y105 2,786,552 74,305 2.74 234,486 3.09 0.6897
2019-10-04 2019-06-30 13F/A-1 MERCK COM 58933Y105 2,712,247 360,789 15.34 227,467 16.31 0.6954
2019-08-14 2019-06-30 13F MERCK COM 58933Y105 2,712,247 360,789 227,467
2019-10-04 2019-03-31 13F/A-1 Merck MERCK & CO ORD SHS 58933Y105 2,351,458 -104,887 -4.27 195,571 4.20 0.7042
2019-05-13 2019-03-31 13F Merck MERCK & CO ORD SHS 58933Y105 2,351,458 -104,887 195,571
2019-10-04 2018-12-31 13F/A-1 Merck MERCK & CO ORD SHS 58933Y105 2,456,345 -900,841 -26.83 187,689 -21.19 0.7558
2019-02-13 2018-12-31 13F Merck MERCK & CO ORD SHS 58933Y105 2,456,345 -900,841 187,689
2019-10-03 2018-09-30 13F/A-1 Merck MERCK & CO ORD SHS 58933Y105 3,357,186 -790,369 -19.06 238,159 -5.40 0.7686
2018-11-14 2018-09-30 13F Merck MERCK & CO ORD SHS 58933Y105 3,357,186 -790,369 238,159
2018-08-14 2018-06-30 13F Merck MERCK & CO ORD SHS 58933Y105 4,147,555 -51,130 -1.22 251,757 10.08 0.7878
2018-05-15 2018-03-31 13F Merck MERCK & CO ORD SHS 58933Y105 4,198,685 304,192 7.81 228,703 4.36 0.7140
2018-02-14 2017-12-31 13F Merck MERCK & CO ORD SHS 58933Y105 3,894,493 408,915 11.73 219,143 -1.81 0.6674
2017-11-14 2017-09-30 13F Merck MERCK & CO ORD SHS 58933Y105 3,485,578 74,658 2.19 223,182 2.09 0.7042
2017-08-14 2017-06-30 13F Merck MERCK & CO ORD SHS 58933Y105 3,410,920 -88,918 -2.54 218,605 -1.70 0.7163
2017-05-15 2017-03-31 13F Merck MERCK & CO ORD SHS 58933Y105 3,499,838 -285,318 -7.54 222,379 -0.20 0.7454
2017-02-09 2016-12-31 13F Merck MERCK & CO ORD SHS 58933Y105 3,785,156 524,839 16.10 222,832 9.51 0.7835
2016-11-14 2016-09-30 13F Merck MERCK & CO ORD SHS 58933Y105 3,260,317 139,882 4.48 203,476 13.19 0.7678
2016-08-09 2016-06-30 13F Merck MERCK & CO ORD SHS 58933Y105 3,120,435 33,569 1.09 179,768 10.07 0.7055
2016-05-13 2016-03-31 13F Merck MERCK & CO ORD SHS 58933Y105 3,086,866 -99,139 -3.11 163,326 -2.95 0.6625
2016-02-12 2015-12-31 13F Merck Merck & Co Inc 58933Y105 3,186,005 64,200 2.06 168,284 9.14 0.6837
2015-11-13 2015-09-30 13F Merck MERCK & CO ORD SHS 58933Y105 3,121,805 244,176 8.49 154,186 -5.88 0.6589
2015-08-14 2015-06-30 13F Merck MERCK & CO ORD SHS 58933Y105 2,877,629 818,600 39.76 163,823 38.42 0.6254
2015-05-15 2015-03-31 13F Merck MERCK & CO ORD SHS 58933Y105 2,059,029 -204,417 -9.03 118,353 -7.93 0.5221
2015-02-13 2014-12-31 13F Merck Merck & Co Inc 58933Y105 2,263,446 -31,135 -1.36 128,541 -5.50 0.5447
2014-11-14 2014-09-30 13F Merck Merck & Co Inc 58933Y105 2,294,581 53,854 2.40 136,022 4.93 0.5627
2014-08-14 2014-06-30 13F Merck Merck & Co Inc 58933Y105 2,240,727 56,988 2.61 129,626 4.56 0.5406
2014-05-15 2014-03-31 13F Merck Merck & Co Inc 58933Y105 2,183,739 -69,756 -3.10 123,970 9.91 0.5513
2014-02-14 2013-12-31 13F MERCK & CO INC COM 58933Y105 2,253,495 205,060 10.01 112,788 15.65 0.4832
2013-12-18 2013-09-30 13F/A-1 MERCK & CO INC COM 58933Y105 2,048,435 -340,293 -14.25 97,526 -12.10 0.4970
2013-11-15 2013-09-30 13F MERCK & CO INC COM 58933Y105 1,963,936 93,503
2013-08-15 2013-06-30 13F MERCK & CO INC COM 58933Y105 2,388,728 2,388,728 110,956 0.6002
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.