Merck & Co., Inc.
MX ˙ BMV ˙ US58933Y1055
SecurityMX:MRK / Merck & Co., Inc.
InstitutionNational Pension Service
Latest Disclosed Ownership5,762,086 shares
Latest Disclosed Value $ 693,121,325
National Pension Service reports 0.47% decrease in ownership of MRK / Merck & Co., Inc.

On May 12, 2026 - National Pension Service filed a 13F-HR form disclosing ownership of 5,762,086 shares of Merck & Co., Inc. (MX:MRK) valued at $693,121,325 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 10, 2026 disclosing 5,789,424 shares of Merck & Co., Inc.. This represents a change in shares of -0.47% 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)
2026-05-12 2026-03-31 13F MERCK COM 58933Y105 5,762,086 -27,338 -0.47 693,121 13.74 0.5264
2026-02-10 2025-12-31 13F MERCK MERCK & CO INC 58933Y105 5,789,424 82,039 1.44 609,395 27.22 0.4512
2025-11-04 2025-09-30 13F MERCK COM 58933Y105 5,707,385 175,582 3.17 479,021 9.39 0.3720
2025-08-08 2025-06-30 13F MERCK COM 58933Y105 5,531,803 258,320 4.90 437,898 -7.49 0.3781
2025-05-13 2025-03-31 13F MERCK COM 58933Y105 5,273,483 312,035 6.29 473,348 -4.10 0.4550
2025-02-05 2024-12-31 13F MERCK COM 58933Y105 4,961,448 175,184 3.66 493,565 -9.19 0.4671
2024-10-30 2024-09-30 13F MERCK&COINC COM 58933Y105 4,786,264 635,176 15.30 543,528 5.76 0.5242
2024-08-13 2024-06-30 13F MERCK COM 58933Y105 4,151,088 68,606 1.68 513,905 -4.60 0.5905
2024-05-14 2024-03-31 13F MERCK COM 58933Y105 4,082,482 50,436 1.25 538,684 22.55 0.6464
2024-02-07 2023-12-31 13F MERCK COM 58933Y105 4,032,046 77,044 1.95 439,574 5.46 0.6121
2023-11-15 2023-09-30 13F MERCK COM 58933Y105 3,955,002 79,627 2.05 416,818 -5.27 0.6670
2023-08-16 2023-06-30 13F MERCK COM 58933Y105 3,875,375 161,981 4.36 440,010 11.87 0.7097
2023-05-12 2023-03-31 13F MERCK COM 58933Y105 3,713,394 59,340 1.62 393,323 -2.98 0.7162
2023-02-24 2022-12-31 13F/A-1 MERCK COM 58933Y105 3,654,054 72,099 2.01 405,417 30.64 0.7975
2023-02-21 2022-12-31 13F MERCK COM 58933Y105 3,654,054 72,099 405 0.7975
2023-02-24 2022-09-30 13F/A-1 MERCK COM 58933Y105 3,581,955 70,121 2.00 310,341 -3.07 0.6476
2022-11-18 2022-09-30 13F MERCK COM 58933Y105 3,581,955 70,121 310,341 0.6476
2022-08-17 2022-06-30 13F MERCK COM 58933Y105 3,511,834 255,239 7.84 320,174 19.82 0.6600
2022-05-13 2022-03-31 13F MERCK COM 58933Y105 3,256,595 18,436 0.57 267,204 7.67 0.4878
2022-02-15 2021-12-31 13F MERCK COM 58933Y105 3,238,159 -35,730 -1.09 248,173 0.92 0.4330
2021-11-18 2021-09-30 13F MERCK COM 58933Y105 3,273,889 -20,510 -0.62 245,902 -4.02 0.4682
2021-08-17 2021-06-30 13F MERCK COM 58933Y105 3,294,399 48,380 1.49 256,205 2.39 0.4867
2021-05-14 2021-03-31 13F MERCK & CO. COM 58933Y105 3,246,019 246,993 8.24 250,236 2.00 0.5235
2021-02-19 2020-12-31 13F MERCK & CO. COM 58933Y105 2,999,026 73,309 2.51 245,320 1.32 0.5593
2020-11-13 2020-09-30 13F MERCK & CO. COM 58933Y105 2,925,717 0 0.00 242,132 7.02 0.6360
2020-08-11 2020-06-30 13F MERCK & CO. COM 58933Y105 2,925,717 -78 -0.00 226,246 0.50 0.6462
2020-05-27 2020-03-31 13F MERCK & CO. COM 58933Y105 2,925,795 32,935 1.14 225,111 -14.44 0.7619
2020-02-21 2019-12-31 13F MERCK COM 58933Y105 2,892,860 64,863 2.29 263,106 10.52 0.7218
2019-11-15 2019-09-30 13F MERCK COM 58933Y105 2,827,997 133,656 4.96 238,061 5.37 0.7533
2019-08-14 2019-06-30 13F MERCK COM 58933Y105 2,694,341 176,290 7.00 225,920 7.88 0.7551
2019-05-15 2019-03-31 13F MERCK COM 58933Y105 2,518,051 94,001 3.88 209,426 9.44 0.8056
2019-02-15 2018-12-31 13F MERCK COM 58933Y105 2,424,050 140,844 6.17 191,355 18.14 0.7894
2018-11-15 2018-09-30 13F MERCK COM 58933Y105 2,283,206 -12,587 -0.55 161,971 17.00 0.6594
2018-08-14 2018-06-30 13F MERCK COM 58933Y105 2,295,793 116,869 5.36 138,436 16.64 0.6264
2018-04-13 2018-03-31 13F MERCK COM 58933Y105 2,178,924 45,662 2.14 118,686 -1.13 0.5883
2018-01-17 2017-12-31 13F MERCK COM 58933Y105 2,133,262 69,293 3.36 120,039 -9.54 0.5993
2017-10-16 2017-09-30 13F MERCK COM 58933Y105 2,063,969 82,967 4.19 132,693 4.11 0.7302
2017-07-13 2017-06-30 13F MERCK COM 58933Y105 1,981,002 171,969 9.51 127,458 11.04 0.7592
2017-04-11 2017-03-31 13F MERCK COM 58933Y105 1,809,033 9,751 0.54 114,783 8.36 0.7684
2017-01-18 2016-12-31 13F MERCK COM 58933Y105 1,799,282 128,030 7.66 105,924 1.55 0.7246
2016-10-14 2016-09-30 13F MERCK COM 58933Y105 1,671,252 135,375 8.81 104,303 17.88 0.8359
2016-08-11 2016-06-30 13F MERCK COM 58933Y105 1,535,877 146,954 10.58 88,482 20.40 0.7855
2016-05-16 2016-03-31 13F MERCK & CO INC COM 58933Y105 1,388,923 56,464 4.24 73,488 4.42 0.7361
2016-02-12 2015-12-31 13F MERCK & CO INC COM 58933Y105 1,332,459 81,510 6.52 70,380 13.91 0.7392
2015-10-15 2015-09-30 13F MERCK & CO INC COM 58933Y105 1,250,949 172,136 15.96 61,784 0.60 0.7812
2015-07-15 2015-06-30 13F MERCK & CO INC COM 58933Y105 1,078,813 153,809 16.63 61,416 15.51 0.7967
2015-04-15 2015-03-31 13F MERCK & CO INC COM 58933Y105 925,004 129,937 16.34 53,169 17.76 0.7682
2015-01-13 2014-12-31 13F MERCK & CO INC COM 58933Y105 795,067 -82,654 -9.42 45,152 -13.22 0.7620
2014-11-07 2014-09-30 13F MERCK & CO INC COM 58933Y105 877,721 877,721 52,031 0.8262
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.