Merck & Co., Inc.
BG ˙ BUL ˙ US58933Y1055
SecurityBG:6MK / Merck & Co., Inc.
InstitutionCorundum Group, Inc.
Latest Disclosed Ownership10,498 shares
Latest Disclosed Value $ 1,262,804
Corundum Group, Inc. reports 9.85% increase in ownership of 6MK / Merck & Co., Inc.

On April 20, 2026 - Corundum Group, Inc. filed a 13F-HR form disclosing ownership of 10,498 shares of Merck & Co., Inc. (BG:6MK) valued at $1,262,804 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 12, 2026 disclosing 9,557 shares of Merck & Co., Inc.. This represents a change in shares of 9.85% 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)
2026-04-20 2026-03-31 13F MERCK CS 58933Y105 10,498 941 9.85 1,263 25.57 0.4221
2026-01-12 2025-12-31 13F MERCK CS 58933Y105 9,557 -187 -1.92 1,006 23.01 0.3376
2025-10-24 2025-09-30 13F MERCK CS 58933Y105 9,744 123 1.28 818 7.36 0.3360
2025-07-21 2025-06-30 13F MERCK CS 58933Y105 9,621 -149 -1.53 762 -13.13 0.3367
2025-04-23 2025-03-31 13F MERCK CS 58933Y105 9,770 -1,886 -16.18 877 -24.42 0.4206
2025-01-16 2024-12-31 13F MERCK CS 58933Y105 11,656 1,002 9.40 1,160 -4.14 0.4330
2024-10-21 2024-09-30 13F MERCK CS 58933Y105 10,654 -6,325 -37.25 1,210 -42.48 0.5520
2024-07-17 2024-06-30 13F MERCK CS 58933Y105 16,979 6,493 61.92 2,102 51.99 0.8212
2024-04-15 2024-03-31 13F MERCK CS 58933Y105 10,486 1,290 14.03 1,384 38.02 0.6673
2024-01-24 2023-12-31 13F MERCK CS 58933Y105 9,196 -2,585 -21.94 1,003 -17.33 0.5027
2023-10-17 2023-09-30 13F MERCK CS 58933Y105 11,781 -1,275 -9.77 1,213 -19.52 0.6891
2023-07-21 2023-06-30 13F MERCK CS 58933Y105 13,056 -4,748 -26.67 1,507 -20.49 0.7514
2023-04-24 2023-03-31 13F MERCK CS 58933Y105 17,804 5,000 39.05 1,894 189,300.00 0.8960
2023-01-12 2022-12-31 13F MERCK CS 58933Y105 12,804 4,604 56.15 1 -99.86 0.8024
2022-10-18 2022-09-30 13F MERCK CS 58933Y105 8,200 382 4.89 706 -0.98 0.4441
2022-07-25 2022-06-30 13F MERCK CS 58933Y105 7,818 900 13.01 713 25.53 0.4817
2022-05-02 2022-03-31 13F MERCK CS 58933Y105 6,918 1,580 29.60 568 38.88 0.5279
2022-02-07 2021-12-31 13F MERCK CS 58933Y105 5,338 660 14.11 409 16.52 0.2663
2021-11-02 2021-09-30 13F MERCK CS 58933Y105 4,678 915 24.32 351 19.80 0.2602
2021-08-02 2021-06-30 13F MERCK CS 58933Y105 3,763 585 18.41 293 19.59 0.1922
2021-05-10 2021-03-31 13F MERCK CS 58933Y105 3,178 88 2.85 245 -3.16 0.1915
2021-02-03 2020-12-31 13F MERCK CS 58933Y105 3,090 346 12.61 253 10.96 0.2108
2020-11-12 2020-09-30 13F/A-1 MERCK CS 58933Y105 2,744 2,744 228 0.2209
2020-08-07 2020-06-30 13F/A-1 MERCK CS 58933Y105 0 -2,805 -100.00 0 -100.00
2020-05-07 2020-03-31 13F/A-1 MERCK CS 58933Y105 2,805 -257 -8.39 216 -22.30 0.3071
2020-01-28 2019-12-31 13F MERCK CS 58933Y105 3,062 118 4.01 278 12.10 0.2919
2019-11-01 2019-09-30 13F/A-1 MERCK CS 58933Y105 2,944 -3 -0.10 248 0.40 0.2873
2019-08-02 2019-06-30 13F MERCK CS 58933Y105 2,947 22 0.75 247 1.65 0.2838
2019-05-08 2019-03-31 13F MERCK CS 58933Y105 2,925 -6,784 -69.87 243 -67.25 0.2780
2019-02-19 2018-12-31 13F MERCK CS 58933Y105 9,709 9,709 742 0.6812
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.