Merck & Co., Inc.
MX ˙ BMV ˙ US58933Y1055
SecurityMX:MRK / Merck & Co., Inc.
InstitutionJohn G Ullman & Associates Inc
Latest Disclosed Ownership94,272 shares
Latest Disclosed Value $ 11,339,936
John G Ullman & Associates Inc reports 6.96% decrease in ownership of MRK / Merck & Co., Inc.

On May 6, 2026 - John G Ullman & Associates Inc filed a 13F-HR form disclosing ownership of 94,272 shares of Merck & Co., Inc. (MX:MRK) valued at $11,339,936 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 5, 2026 disclosing 101,322 shares of Merck & Co., Inc.. This represents a change in shares of -6.96% 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)
2026-05-06 2026-03-31 13F MERCK COM 58933Y105 94,272 -7,050 -6.96 11,340 6.32 1.5034
2026-02-05 2025-12-31 13F MERCK COM 58933Y105 101,322 2,616 2.65 10,665 28.74 1.4221
2025-11-05 2025-09-30 13F MERCK COM 58933Y105 98,706 4,393 4.66 8,284 10.97 1.1155
2025-07-29 2025-06-30 13F MERCK COM 58933Y105 94,313 396 0.42 7,466 -11.45 1.1080
2025-05-06 2025-03-31 13F MERCK COM 58933Y105 93,917 -2,506 -2.60 8,430 -12.11 1.3002
2025-02-05 2024-12-31 13F MERCK COM 58933Y105 96,423 -1,049 -1.08 9,592 -13.34 1.4114
2024-11-08 2024-09-30 13F MERCK COM 58933Y105 97,472 1 0.00 11,069 -8.27 1.5915
2024-08-08 2024-06-30 13F MERCK COM 58933Y105 97,471 -728 -0.74 12,067 -6.88 1.8409
2024-05-06 2024-03-31 13F MERCK COM 58933Y105 98,199 -600 -0.61 12,957 20.30 1.9879
2024-01-31 2023-12-31 13F MERCK COM 58933Y105 98,799 -1,070 -1.07 10,771 4.77 1.7084
2023-11-01 2023-09-30 13F MERCK COM 58933Y105 99,869 -950 -0.94 10,282 -11.62 1.6818
2023-08-21 2023-06-30 13F MERCK COM 58933Y105 100,819 -872 -0.86 11,634 116,230.00 1.7949
2023-05-05 2023-03-31 13F MERCK COM 58933Y105 101,691 -663 -0.65 11 -9.09 1.6826
2023-02-08 2022-12-31 13F MERCK COM 58933Y105 102,354 -31,118 -23.31 11 -99.90 1.8106
2022-10-19 2022-09-30 13F MERCK COM 58933Y105 133,472 -1,447 -1.07 11,495 -6.55 2.0113
2022-07-27 2022-06-30 13F MERCK COM 58933Y105 134,919 32 0.02 12,301 11.15 1.9740
2022-04-29 2022-03-31 13F MERCK COM 58933Y105 134,887 104 0.08 11,067 7.13 1.5334
2022-01-26 2021-12-31 13F MERCK COM 58933Y105 134,783 7,260 5.69 10,330 7.85 1.4207
2021-11-02 2021-09-30 13F MERCK COM 58933Y105 127,523 48,100 60.56 9,578 55.06 1.3027
2021-07-23 2021-06-30 13F MERCK COM 58933Y105 79,423 -500 -0.63 6,177 0.26 0.8047
2021-04-22 2021-03-31 13F MERCK COM 58933Y105 79,923 -900 -1.11 6,161 -6.81 0.8265
2021-02-05 2020-12-31 13F MERCK COM 58933Y105 80,823 -583 -0.72 6,611 -2.10 1.0248
2020-11-06 2020-09-30 13F MERCK COM 58933Y105 81,406 -133 -0.16 6,753 7.11 1.3977
2020-07-29 2020-06-30 13F MERCK COM 58933Y105 81,539 -383 -0.47 6,305 0.03 1.5387
2020-04-14 2020-03-31 13F MERCK COM 58933Y105 81,922 -144 -0.18 6,303 -15.55 1.6720
2020-01-29 2019-12-31 13F MERCK COM 58933Y105 82,066 -2,000 -2.38 7,464 5.47 1.2849
2019-10-21 2019-09-30 13F MERCK COM 58933Y105 84,066 -1,609 -1.88 7,077 -1.49 1.2854
2019-08-02 2019-06-30 13F MERCK COM 58933Y105 85,675 -54,400 -38.84 7,184 -38.33 1.2635
2019-04-30 2019-03-31 13F MERCK COM 58933Y105 140,075 -56,936 -28.90 11,650 -22.61 2.1093
2019-01-29 2018-12-31 13F MERCK COM 58933Y105 197,011 -53,452 -21.34 15,053 -15.28 3.0363
2018-11-02 2018-09-30 13F MERCK COM 58933Y105 250,463 -1,100 -0.44 17,768 16.36 3.2303
2018-07-23 2018-06-30 13F MERCK COM 58933Y105 251,563 12,676 5.31 15,270 17.35 2.8879
2018-04-19 2018-03-31 13F MERCK COM 58933Y105 238,887 34,719 17.01 13,012 13.26 2.5160
2018-01-31 2017-12-31 13F MERCK COM 58933Y105 204,168 -3,001 -1.45 11,489 -13.39 2.2920
2017-11-03 2017-09-30 13F MERCK COM 58933Y105 207,169 -3,133 -1.49 13,265 -1.58 2.5864
2017-07-26 2017-06-30 13F MERCK COM 58933Y105 210,302 -2,350 -1.11 13,478 -0.25 2.6744
2017-04-25 2017-03-31 13F MERCK & CO. INC. MRK COM 58933Y105 212,652 -2,170 -1.01 13,512 6.84 2.7936
2017-01-20 2016-12-31 13F MERCK & CO. INC. MRK COM 58933Y105 214,822 -2,475 -1.14 12,647 -6.75 2.6495
2016-10-20 2016-09-30 13F MERCK & CO. INC. MRK COM 58933Y105 217,297 -5,450 -2.45 13,562 5.69 2.7891
2016-07-22 2016-06-30 13F MERCK & CO. INC. MRK COM 58933Y105 222,747 -2,925 -1.30 12,832 7.47 2.6351
2016-04-27 2016-03-31 13F MERCK & CO. INC. MRK COM 58933Y105 225,672 2,840 1.27 11,940 1.44 2.8014
2016-02-11 2015-12-31 13F MERCK & CO. INC. MRK COM 58933Y105 222,832 9,973 4.69 11,770 11.96 2.6008
2015-10-23 2015-09-30 13F/A-1 MERCK & CO. INC. MRK COM 58933Y105 212,859 23,420 12.36 10,513 -2.52 2.4944
2015-10-21 2015-09-30 13F MERCK & CO. INC. MRK COM 58933Y105 189,439 10,785
2015-08-11 2015-06-30 13F MERCK & CO. INC. MRK COM 58933Y105 189,439 -9,290 -4.67 10,785 -5.59 2.0302
2015-05-13 2015-03-31 13F MERCK & CO INC COM 58933Y105 198,729 -3,975 -1.96 11,423 -0.77 2.1710
2015-01-26 2014-12-31 13F MERCK & CO INC COM 58933Y105 202,704 -2,475 -1.21 11,512 -5.35 2.1677
2014-11-12 2014-09-30 13F MERCK & CO INC COM 58933Y105 205,179 -4,030 -1.93 12,163 0.50 2.3397
2014-07-18 2014-06-30 13F MERCK & CO INC COM 58933Y105 209,209 -4,800 -2.24 12,103 -0.38 2.2104
2014-05-07 2014-03-31 13F MERCK & CO INC COM 58933Y105 214,009 825 0.39 12,149 13.86 2.2503
2014-02-03 2013-12-31 13F MERCK & CO INC COM 58933Y105 213,184 12,182 6.06 10,670 11.49 2.0369
2013-11-04 2013-09-30 13F MERCK & CO INC COM 58933Y105 201,002 -1,482 -0.73 9,570 1.75 1.9488
2013-08-14 2013-06-30 13F MERCK & CO INC COM 58933Y105 202,484 202,484 9,405 1.9637
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.