Merck & Co., Inc.
MX ˙ BMV ˙ US58933Y1055
SecurityMX:MRK / Merck & Co., Inc.
InstitutionSt. Louis Trust Co
Latest Disclosed Ownership16,457 shares
Latest Disclosed Value $ 1,979,613
St. Louis Trust Co reports 6.26% increase in ownership of MRK / Merck & Co., Inc.

On May 14, 2026 - St. Louis Trust Co filed a 13F-HR form disclosing ownership of 16,457 shares of Merck & Co., Inc. (MX:MRK) valued at $1,979,613 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 9, 2026 disclosing 15,488 shares of Merck & Co., Inc.. This represents a change in shares of 6.26% 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 16,457 969 6.26 1,980 21.41 0.1740
2026-02-09 2025-12-31 13F MERCK COM 58933Y105 15,488 0 0.00 1,630 25.48 0.1366
2025-11-07 2025-09-30 13F MERCK COM 58933Y105 15,488 0 0.00 1,300 5.95 0.1621
2025-07-25 2025-06-30 13F MERCK COM 58933Y105 15,488 0 0.00 1,226 -11.80 0.1633
2025-05-05 2025-03-31 13F MERCK COM 58933Y105 15,488 1,700 12.33 1,390 1.39 0.2014
2025-02-07 2024-12-31 13F MERCK COM 58933Y105 13,788 0 0.00 1,372 -12.40 0.1961
2024-11-07 2024-09-30 13F MERCK COM 58933Y105 13,788 -1,700 -10.98 1,566 -18.36 0.2203
2024-07-30 2024-06-30 13F MERCK COM 58933Y105 15,488 0 0.00 1,917 -6.17 0.2932
2024-05-02 2024-03-31 13F MERCK COM 58933Y105 15,488 1,350 9.55 2,044 32.58 0.3194
2024-02-05 2023-12-31 13F MERCK COM 58933Y105 14,138 350 2.54 1,541 8.60 0.2653
2023-11-03 2023-09-30 13F MERCK COM 58933Y105 13,788 0 0.00 1,419 -10.75 0.2673
2023-08-03 2023-06-30 13F MERCK COM 58933Y105 13,788 0 0.00 1,591 8.46 0.2931
2023-05-04 2023-03-31 13F MERCK COM 58933Y105 13,788 0 0.00 1,467 -4.12 0.2948
2023-02-06 2022-12-31 13F MERCK COM 58933Y105 13,788 453 3.40 1,530 40.15 0.3253
2022-11-02 2022-09-30 13F MERCK COM 58933Y105 13,335 -453 -3.29 1,091 -13.21 0.3103
2022-08-01 2022-06-30 13F MERCK COM 58933Y105 13,788 0 0.00 1,257 11.04 0.2716
2022-05-13 2022-03-31 13F MERCK COM 58933Y105 13,788 0 0.00 1,132 7.20 0.2424
2022-02-07 2021-12-31 13F MERCK COM 58933Y105 13,788 0 0.00 1,056 2.03 0.2229
2021-11-12 2021-09-30 13F MERCK COM 58933Y105 13,788 -2,286 -14.22 1,035 -17.20 0.2730
2021-08-06 2021-06-30 13F MERCK COM 58933Y105 16,074 0 0.00 1,250 0.89 0.3096
2021-04-27 2021-03-31 13F MERCK & CO. COM 58933Y105 16,074 0 0.00 1,239 -5.78 0.3055
2021-02-03 2020-12-31 13F MERCK & CO. COM 58933Y105 16,074 0 0.00 1,315 -1.35 0.3796
2020-10-27 2020-09-30 13F MERCK & CO. COM 58933Y105 16,074 0 0.00 1,333 7.24 0.4266
2020-08-06 2020-06-30 13F MERCK & CO. COM 58933Y105 16,074 0 0.00 1,243 0.49 0.3721
2020-05-04 2020-03-31 13F MERCK & CO. COM 58933Y105 16,074 0 0.00 1,237 -15.39 0.4673
2020-02-05 2019-12-31 13F MERCK COM 58933Y105 16,074 0 0.00 1,462 8.06 0.4164
2019-10-30 2019-09-30 13F MERCK COM 58933Y105 16,074 -3,294 -17.01 1,353 -16.69 0.4194
2019-07-30 2019-06-30 13F MERCK COM 58933Y105 19,368 0 0.00 1,624 0.81 0.5132
2019-05-10 2019-03-31 13F MERCK COM 58933Y105 19,368 0 0.00 1,611 8.85 0.5187
2019-01-31 2018-12-31 13F MERCK COM 58933Y105 19,368 0 0.00 1,480 7.71 0.5359
2018-10-31 2018-09-30 13F MERCK COM 58933Y105 19,368 -10,918 -36.05 1,374 -25.29 0.4696
2018-08-07 2018-06-30 13F MERCK COM 58933Y105 30,286 2,918 10.66 1,839 23.34 0.6144
2018-04-23 2018-03-31 13F MERCK COM 58933Y105 27,368 9,288 51.37 1,491 46.61 0.5118
2018-01-25 2017-12-31 13F MERCK COM 58933Y105 18,080 0 0.00 1,017 -12.18 0.4005
2017-11-14 2017-09-30 13F MERCK COM 58933Y105 18,080 -2,400 -11.72 1,158 -11.81 0.5134
2017-07-31 2017-06-30 13F MERCK COM 58933Y105 20,480 0 0.00 1,313 0.92 0.6045
2017-05-01 2017-03-31 13F MERCK COM 58933Y105 20,480 0 0.00 1,301 7.88 0.5565
2017-02-09 2016-12-31 13F MERCK COM 58933Y105 20,480 -127 -0.62 1,206 -6.22 0.5718
2016-11-08 2016-09-30 13F MERCK COM 58933Y105 20,607 -864 -4.02 1,286 3.96 0.6171
2016-08-05 2016-06-30 13F MERCK COM 58933Y105 21,471 -2,998 -12.25 1,237 -4.48 0.6570
2016-05-11 2016-03-31 13F MERCK & CO INC COM 58933Y105 24,469 -331 -1.33 1,295 -1.15 0.7060
2016-02-11 2015-12-31 13F MERCK & CO INC COM 58933Y105 24,800 24,800 1,310 0.8273
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.