Merck & Co., Inc.
MX ˙ BMV ˙ US58933Y1055
SecurityMX:MRK / Merck & Co., Inc.
InstitutionNorthwestern Mutual Wealth Management Co
Latest Disclosed Ownership427,111 shares
Latest Disclosed Value $ 51,377,368
Northwestern Mutual Wealth Management Co reports 2.55% increase in ownership of MRK / Merck & Co., Inc.

On May 7, 2026 - Northwestern Mutual Wealth Management Co filed a 13F-HR form disclosing ownership of 427,111 shares of Merck & Co., Inc. (MX:MRK) valued at $51,377,368 USD as of March 31, 2026. The entity filed a previous 13F-HR/A on February 10, 2026 disclosing 416,488 shares of Merck & Co., Inc.. This represents a change in shares of 2.55% 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)
2026-05-07 2026-03-31 13F MERCK COM 58933Y105 427,111 10,623 2.55 51,377 17.19 0.0316
2026-02-10 2025-12-31 13F/A-1 MERCK COM 58933Y105 416,488 112,341 36.94 43,840 71.74 0.0277
2026-02-05 2025-12-31 13F MERCK COM 58933Y105 8,571 -295,576 219 0.0001
2025-11-14 2025-09-30 13F MERCK COM 58933Y105 304,147 3,795 1.26 25,527 7.37 0.0170
2025-08-13 2025-06-30 13F MERCK COM 58933Y105 300,352 -14,140 -4.50 23,776 -15.78 0.0173
2025-05-14 2025-03-31 13F MERCK COM 58933Y105 314,492 7,496 2.44 28,229 -7.57 0.0231
2025-02-11 2024-12-31 13F MERCK COM 58933Y105 306,996 -7,384 -2.35 30,540 -14.45 0.0258
2024-11-12 2024-09-30 13F MERCK COM 58933Y105 314,380 2,128 0.68 35,701 -7.65 0.0317
2024-08-16 2024-06-30 13F MERCK COM 58933Y105 312,252 9,174 3.03 38,657 -3.34 0.0381
2024-05-15 2024-03-31 13F MERCK COM 58933Y105 303,078 1,154 0.38 39,992 21.50 0.0411
2024-02-13 2023-12-31 13F MERCK COM 58933Y105 301,924 -30,806 -9.26 32,915 -3.91 0.0371
2023-11-14 2023-09-30 13F MERCK COM 58933Y105 332,730 -21,004 -5.94 34,254 -16.08 0.0445
2023-08-14 2023-06-30 13F MERCK COM 58933Y105 353,734 7,357 2.12 40,817 10.76 0.0528
2023-05-15 2023-03-31 13F MERCK COM 58933Y105 346,377 2,025 0.59 36,851 -3.54 0.0514
2023-02-21 2022-12-31 13F MERCK COM 58933Y105 344,352 4,477 1.32 38,206 30.53 0.0578
2022-11-14 2022-09-30 13F MERCK COM 58933Y105 339,875 19,772 6.18 29,270 0.29 0.0511
2022-08-04 2022-06-30 13F MERCK COM 58933Y105 320,103 5,840 1.86 29,184 13.18 0.0501
2022-05-09 2022-03-31 13F MERCK COM 58933Y105 314,263 2,207 0.71 25,786 7.82 0.0413
2022-02-03 2021-12-31 13F MERCK COM 58933Y105 312,056 15,601 5.26 23,915 7.41 0.0391
2021-11-15 2021-09-30 13F MERCK COM 58933Y105 296,455 -247,515 -45.50 22,266 -47.37 0.0407
2021-08-13 2021-06-30 13F MERCK COM 58933Y105 543,970 26,348 5.09 42,304 6.01 0.0803
2021-05-14 2021-03-31 13F MERCK & CO. COM 58933Y105 517,622 39,624 8.29 39,904 2.05 0.0847
2021-02-12 2020-12-31 13F MERCK & CO. COM 58933Y105 477,998 11,780 2.53 39,102 1.11 0.0903
2020-11-13 2020-09-30 13F MERCK & CO. COM 58933Y105 466,218 21,158 4.75 38,673 12.37 0.1041
2020-08-14 2020-06-30 13F MERCK & CO. COM 58933Y105 445,060 24,702 5.88 34,417 6.42 0.1062
2020-05-08 2020-03-31 13F MERCK & CO. COM 58933Y105 420,358 26,591 6.75 32,342 -9.69 0.1249
2020-02-13 2019-12-31 13F MERCK COM 58933Y105 393,767 7,226 1.87 35,813 10.06 0.1221
2019-11-12 2019-09-30 13F MERCK COM 58933Y105 386,541 11,546 3.08 32,539 3.48 0.1236
2019-08-12 2019-06-30 13F MERCK COM 58933Y105 374,995 5,005 1.35 31,444 2.19 0.1264
2019-05-10 2019-03-31 13F MERCK COM 58933Y105 369,990 5,701 1.56 30,770 10.54 0.1347
2019-02-12 2018-12-31 13F MERCK COM 58933Y105 364,289 62,760 20.81 27,836 30.13 0.1394
2018-11-01 2018-09-30 13F MERCK COM 58933Y105 301,529 7,425 2.52 21,391 19.82 0.1079
2018-08-10 2018-06-30 13F MERCK COM 58933Y105 294,104 -37,147 -11.21 17,852 -1.06 0.1000
2018-05-14 2018-03-31 13F MERCK COM 58933Y105 331,251 14,605 4.61 18,044 1.27 0.1095
2018-01-31 2017-12-31 13F MERCK COM 58933Y105 316,646 -13,728 -4.16 17,818 -15.77 0.1135
2017-11-07 2017-09-30 13F MERCK COM 58933Y105 330,374 10,754 3.36 21,154 3.27 0.1513
2017-08-10 2017-06-30 13F MERCK COM 58933Y105 319,620 30,520 10.56 20,485 11.51 0.1645
2017-05-09 2017-03-31 13F MERCK COM 58933Y105 289,100 19,311 7.16 18,370 15.67 0.1671
2017-02-15 2016-12-31 13F MERCK COM 58933Y105 269,789 147,302 120.26 15,881 107.76 0.1723
2017-02-23 2016-09-30 13F/A-2 MERCK COM 58933Y105 122,487 -15,911 -11.50 7,644 -4.13 0.5044
2016-11-14 2016-09-30 13F MERCK COM 58933Y105 133,538 8,334
2016-08-29 2016-06-30 13F MERCK COM 58933Y105 138,398 6,736 5.12 7,973 14.41 0.1143
2016-05-16 2016-03-31 13F MERCK & CO INC COM 58933Y105 131,662 22,350 20.45 6,969 20.68 0.1129
2016-02-16 2015-12-31 13F MERCK & CO INC COM 58933Y105 109,312 10,445 10.56 5,775 18.27 0.1152
2015-11-16 2015-09-30 13F MERCK & CO INC COM 58933Y105 98,867 8,867 9.85 4,883 -4.70 0.1163
2015-09-30 2015-06-30 13F/A-1 MERCK & CO INC COM 58933Y105 90,000 7,032 8.48 5,124 7.44 0.1329
2015-08-14 2015-06-30 13F MERCK & CO INC COM 58933Y105 78,479 4,510
2015-05-15 2015-03-31 13F MERCK & CO INC COM 58933Y105 82,968 -1,118 -1.33 4,769 -0.15 0.1334
2015-02-13 2014-12-31 13F MERCK & CO INC COM 58933Y105 84,086 6,761 8.74 4,776 4.19 0.1474
2014-11-14 2014-09-30 13F MERCK & CO INC COM 58933Y105 77,325 8,262 11.96 4,584 14.74 0.1603
2014-08-05 2014-06-30 13F MERCK & CO INC COM 58933Y105 69,063 -3,661 -5.03 3,995 -3.22 0.1559
2014-05-15 2014-03-31 13F MERCK & CO INC COM 58933Y105 72,724 1,454 2.04 4,128 15.73 0.1727
2014-02-14 2013-12-31 13F MERCK & CO INC COM 58933Y105 71,270 2,872 4.20 3,567 9.55 0.1621
2013-11-14 2013-09-30 13F MERCK & CO INC COM 58933Y105 68,398 -1,828 -2.60 3,256 -0.18 0.1712
2013-08-21 2013-06-30 13F/A-1 MERCK & CO INC COM 58933Y105 70,226 70,226 3,262 0.1950
2013-08-14 2013-06-30 13F MERCK & CO INC COM 58933Y105 922,293 42,841 0.4710
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.