Merck & Co., Inc.
MX ˙ BMV ˙ US58933Y1055
SecurityMX:MRK / Merck & Co., Inc.
InstitutionOak Grove Capital LLC
Latest Disclosed Ownership82,960 shares
Latest Disclosed Value $ 9,979,258
Oak Grove Capital LLC ownership in MRK / Merck & Co., Inc.

On May 13, 2026 - Oak Grove Capital LLC filed a 13F-HR form disclosing ownership of 82,960 shares of Merck & Co., Inc. (MX:MRK) valued at $9,979,258 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 26, 2026 disclosing 82,260 shares of Merck & Co., Inc.. This represents a change in shares of 0.85% during the quarter.

Oak Grove Capital LLC has a history of taking positions in derivatives of the underlying security (MRK) in the form of stock options. The firm currently holds call options representing 0 of underlying shares valued at $0 USD .

Note: prior versions of this page mistakenly stated that the share values represented the number of options, not the number of underlying shares. For more information on the data backing these reports, please see the SEC document Frequently Asked Questions About Form 13F.

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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Institutional Put/Call Ratios
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In addition to reporting standard equity and debt issues, institutions with more than 100MM assets under management must also disclose their put and call option holdings. Since put options generally indicate negative sentiment, and call options indicate positive sentiment, we can get a sense of the overall institutional sentiment by plotting the ratio of puts to calls. The chart to the right plots the historical put/call ratio for this instrument.

Using Put/Call Ratio as an indicator of investor sentiment overcomes one of the key deficiencies of using total institutional ownership, which is that a significant amount of assets under management are invested passively to track indices. Passively-managed funds do not typically buy options, so the put/call ratio indicator more closely tracks the sentiment of actively-managed funds.

MX:MRK / Merck & Co., Inc. Historical Put/Call Ratio
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 82,960 700 0.85 9,979 15.26 0.8456
2026-02-26 2025-12-31 13F MERCK COM 58933Y105 82,260 -8,555 -9.42 8,659 13.59 1.0261
2025-11-12 2025-09-30 13F MERCK COM 58933Y105 90,815 -21,515 -19.15 7,622 -14.28 1.0795
2025-08-01 2025-06-30 13F MERCK COM 58933Y105 112,330 -66,880 -37.32 8,892 -44.72 1.4567
2025-05-13 2025-03-31 13F MERCK COM 58933Y105 179,210 27,700 18.28 16,086 6.72 3.3531
2025-02-06 2024-12-31 13F MERCK COM 58933Y105 151,510 67,272 79.86 15,072 57.56 2.2495
2024-11-13 2024-09-30 13F MERCK COM 58933Y105 84,238 33,977 67.60 9,566 53.74 1.5670
2024-08-05 2024-06-30 13F MERCK COM 58933Y105 50,261 1,944 4.02 6,222 -2.40 1.1317
2024-05-10 2024-03-31 13F MERCK COM 58933Y105 48,317 964 2.04 6,375 23.50 1.2876
2024-02-12 2023-12-31 13F MERCK COM 58933Y105 47,353 27,193 134.89 5,162 148.77 1.3732
2023-11-21 2023-09-30 13F MERCK COM 58933Y105 20,160 2,660 15.20 2,075 2.77 0.7214
2023-08-07 2023-06-30 13F MERCK COM 58933Y105 17,500 3,500 25.00 2,019 35.59 0.6909
2023-05-16 2023-03-31 13F MERCK COM 58933Y105 14,000 5,100 57.30 1,489 50.86 0.6094
2023-02-08 2022-12-31 13F MERCK COM 58933Y105 8,900 0 0.00 987 28.85 0.4961
2022-11-01 2022-09-30 13F MERCK COM 58933Y105 8,900 0 0.00 766 -5.55 0.2586
2022-08-12 2022-06-30 13F MERCK COM 58933Y105 8,900 -500 -5.32 811 5.19 0.2637
2022-05-10 2022-03-31 13F MERCK COM 58933Y105 9,400 0 0.00 771 7.08 0.1562
2022-02-11 2021-12-31 13F MERCK COM 58933Y105 9,400 -1,000 -9.62 720 -7.81 0.1252
2021-11-12 2021-09-30 13F MERCK COM 58933Y105 10,400 0 0.00 781 -3.46 0.1686
2021-08-13 2021-06-30 13F MERCK COM 58933Y105 10,400 0 0.00 809 0.87 0.1809
2021-05-11 2021-03-31 13F MERCK & CO. COM 58933Y105 10,400 -916 -8.09 802 -13.39 0.2240
2021-02-17 2020-12-31 13F MERCK & CO. COM 58933Y105 11,316 -384 -3.28 926 -4.63 0.3024
2020-11-13 2020-09-30 13F MERCK & CO. COM 58933Y105 11,700 -4,800 -29.09 971 -23.90 0.4584
2020-08-24 2020-06-30 13F MERCK & CO. COM 58933Y105 16,500 7,391 81.14 1,276 82.03 0.7689
2020-05-11 2020-03-31 13F MERCK & CO. COM 58933Y105 9,109 -25,600 -73.76 701 -77.80 0.4535
2020-02-05 2019-12-31 13F MERCK COM 58933Y105 34,709 28,563 464.74 3,157 510.64 1.2324
2019-10-30 2019-09-30 13F MERCK COM 58933Y105 6,146 337 5.80 517 6.16 0.2244
2019-08-09 2019-06-30 13F MERCK COM 58933Y105 5,809 -200 -3.33 487 -2.60 0.2607
2019-05-10 2019-03-31 13F MERCK COM 58933Y105 6,009 0 0.00 500 8.93 0.3153
2019-02-15 2018-12-31 13F MERCK COM 58933Y105 6,009 0 0.00 459 7.75 0.4100
2018-11-09 2018-09-30 13F MERCK COM 58933Y105 6,009 -200 -3.22 426 13.00 0.3673
2018-11-09 2018-06-30 13F MERCK COM 58933Y105 6,209 0 0.00 377 11.54 0.3825
2018-11-09 2018-03-31 13F MERCK COM 58933Y105 6,209 -1,800 -22.47 338 -25.06 0.3729
2018-02-12 2017-12-31 13F MERCK COM 58933Y105 8,009 8,009 451 0.4684
Disclosed Call Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share
Price
Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2020-11-13 2020-09-30 13F MERCK & CO. COM Call 0 -100.00 0 n/a n/a n/a
2020-08-24 2020-06-30 13F MERCK & CO. COM Call 200 0 n/a n/a n/a
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.