Merck & Co., Inc.
BG ˙ BUL ˙ US58933Y1055
SecurityBG:6MK / Merck & Co., Inc.
InstitutionBarr E S & Co
Latest Disclosed Ownership4,536 shares
Latest Disclosed Value $ 545,636
Barr E S & Co reports 52.68% decrease in ownership of 6MK / Merck & Co., Inc.

On May 13, 2026 - Barr E S & Co filed a 13F-HR form disclosing ownership of 4,536 shares of Merck & Co., Inc. (BG:6MK) valued at $545,636 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 5, 2026 disclosing 9,586 shares of Merck & Co., Inc.. This represents a change in shares of -52.68% 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)
2026-05-13 2026-03-31 13F MERCK COM 58933Y105 4,536 -5,050 -52.68 546 -45.99 0.0317
2026-02-05 2025-12-31 13F MERCK COM 58933Y105 9,586 5,523 135.93 1,009 195.89 0.0525
2025-11-12 2025-09-30 13F MERCK COM 58933Y105 4,063 -1,101 -21.32 341 -16.42 0.0185
2025-08-12 2025-06-30 13F MERCK COM 58933Y105 5,164 -1,617 -23.85 409 -32.89 0.0234
2025-05-15 2025-03-31 13F MERCK COM 58933Y105 6,781 -1,402 -17.13 609 -25.31 0.0370
2025-02-13 2024-12-31 13F MERCK COM 58933Y105 8,183 1,600 24.31 814 8.97 0.0482
2024-11-14 2024-09-30 13F MERCK COM 58933Y105 6,583 349 5.60 748 -3.11 0.0467
2024-08-14 2024-06-30 13F MERCK COM 58933Y105 6,234 -416 -6.26 772 -12.09 0.0506
2024-05-15 2024-03-31 13F MERCK COM 58933Y105 6,650 0 0.00 877 21.13 0.0572
2024-02-09 2023-12-31 13F MERCK COM 58933Y105 6,650 1,601 31.71 725 39.50 0.0492
2023-11-14 2023-09-30 13F MERCK COM 58933Y105 5,049 -113 -2.19 520 -12.77 0.0376
2023-08-10 2023-06-30 13F MERCK COM 58933Y105 5,162 500 10.73 596 20.20 0.0449
2023-05-15 2023-03-31 13F MERCK COM 58933Y105 4,662 -250 -5.09 496 -9.01 0.0411
2023-02-14 2022-12-31 13F MERCK COM 58933Y105 4,912 0 0.00 545 28.61 0.0452
2022-11-14 2022-09-30 13F MERCK COM 58933Y105 4,912 -300 -5.76 423 -10.95 0.0374
2022-08-15 2022-06-30 13F MERCK COM 58933Y105 5,212 -463 -8.16 475 1.93 0.0387
2022-05-16 2022-03-31 13F MERCK COM 58933Y105 5,675 -900 -13.69 466 -7.54 0.0319
2022-02-14 2021-12-31 13F MERCK COM 58933Y105 6,575 0 0.00 504 2.02 0.0336
2021-11-10 2021-09-30 13F MERCK COM 58933Y105 6,575 -296 -4.31 494 -7.49 0.0356
2021-08-13 2021-06-30 13F MERCK COM 58933Y105 6,871 1,677 32.29 534 33.50 0.0385
2021-05-14 2021-03-31 13F MERCK COM 58933Y105 5,194 0 0.00 400 -5.88 0.0314
2021-02-16 2020-12-31 13F MERCK COM 58933Y105 5,194 0 0.00 425 -1.39 0.0369
2020-11-13 2020-09-30 13F MERCK COM 58933Y105 5,194 0 0.00 431 7.21 0.0426
2020-08-14 2020-06-30 13F MERCK COM 58933Y105 5,194 0 0.00 402 0.50 0.0414
2020-05-15 2020-03-31 13F MERCK COM 58933Y105 5,194 0 0.00 400 -15.25 0.0461
2020-02-14 2019-12-31 13F MERCK COM 58933Y105 5,194 0 0.00 472 8.01 0.0454
2019-11-12 2019-09-30 13F MERCK COM 58933Y105 5,194 0 0.00 437 0.23 0.0432
2019-08-08 2019-06-30 13F MERCK COM 58933Y105 5,194 -150 -2.81 436 -1.80 0.0429
2019-05-15 2019-03-31 13F MERCK COM 58933Y105 5,344 -397 -6.92 444 1.14 0.0460
2019-02-14 2018-12-31 13F MERCK COM 58933Y105 5,741 -417 -6.77 439 0.46 0.0490
2018-11-07 2018-09-30 13F MERCK COM 58933Y105 6,158 25 0.41 437 17.47 0.0430
2018-08-10 2018-06-30 13F MERCK COM 58933Y105 6,133 0 0.00 372 11.38 0.0384
2018-05-15 2018-03-31 13F MERCK COM 58933Y105 6,133 -200 -3.16 334 -6.18 0.0350
2018-02-14 2017-12-31 13F MERCK COM 58933Y105 6,333 102 1.64 356 -10.78 0.0361
2017-11-09 2017-09-30 13F MERCK COM 58933Y105 6,231 0 0.00 399 0.00 0.0425
2017-08-14 2017-06-30 13F MERCK COM 58933Y105 6,231 548 9.64 399 10.53 0.0444
2017-05-15 2017-03-31 13F MERCK COM 58933Y105 5,683 -350 -5.80 361 1.69 0.0412
2017-02-14 2016-12-31 13F MERCK COM 58933Y105 6,033 0 0.00 355 -5.84 0.0417
2016-11-10 2016-09-30 13F MERCK COM 58933Y105 6,033 150 2.55 377 11.21 0.0464
2016-08-12 2016-06-30 13F MERCK COM 58933Y105 5,883 0 0.00 339 9.00 0.0410
2016-05-13 2016-03-31 13F MERCK COM 58933Y105 5,883 -526 -8.21 311 -8.26 0.0375
2016-02-12 2015-12-31 13F MERCK COM 58933Y105 6,409 -50 -0.77 339 6.27 0.0414
2015-11-13 2015-09-30 13F MERCK COM 58933Y105 6,459 115 1.81 319 -11.63 0.0407
2015-08-14 2015-06-30 13F MERCK COM 58933Y105 6,344 0 0.00 361 -1.10 0.0432
2015-05-14 2015-03-31 13F MERCK COM 58933Y105 6,344 -233 -3.54 365 -2.41 0.0428
2015-02-13 2014-12-31 13F MERCK COM 58933Y105 6,577 -486 -6.88 374 -10.74 0.0427
2014-11-13 2014-09-30 13F MERCK COM 58933Y105 7,063 186 2.70 419 5.28 0.0513
2014-08-14 2014-06-30 13F MERCK COM 58933Y105 6,877 0 0.00 398 2.05 0.0482
2014-05-15 2014-03-31 13F MERCK COM 58933Y105 6,877 -770 -10.07 390 1.83 0.0488
2014-02-14 2013-12-31 13F MERCK COM 58933Y105 7,647 1,261 19.75 383 25.99 0.0474
2013-11-14 2013-09-30 13F MERCK COM 58933Y105 6,386 211 3.42 304 5.92 0.0410
2013-08-14 2013-06-30 13F MERCK COM 58933Y105 6,175 6,175 287 0.0398
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.