Merck & Co., Inc.
BG ˙ BUL ˙ US58933Y1055
SecurityBG:6MK / Merck & Co., Inc.
InstitutionCaption Management, LLC
Latest Disclosed Ownership6,500 shares
Latest Disclosed Value $ 781,885
Caption Management, LLC ownership in 6MK / Merck & Co., Inc.

On May 15, 2026 - Caption Management, LLC filed a 13F-HR form disclosing ownership of 6,500 shares of Merck & Co., Inc. (BG:6MK) valued at $781,885 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 126,500 shares of Merck & Co., Inc.. This represents a change in shares of -94.86% during the quarter.

Caption Management, LLC has a history of taking positions in derivatives of the underlying security (6MK) in the form of stock options. The firm currently holds call options representing 0 of underlying shares valued at $0 USD and put options representing 70,000 of underlying shares valued at $8,420,300 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.

BG:6MK / 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)
2026-05-15 2026-03-31 13F MERCK COM 58933Y105 6,500 -120,000 -94.86 782 -94.13 0.0046
2026-02-17 2025-12-31 13F MERCK COM 58933Y105 126,500 121,899 2,649.40 13,315 3,349.48 0.0913
2025-11-14 2025-09-30 13F MERCK COM 58933Y105 4,601 -2,299 -33.32 386 -29.30 0.0030
2025-08-14 2025-06-30 13F MERCK COM 58933Y105 6,900 6,900 546 0.0060
2024-05-15 2024-03-31 13F MERCK COM 58933Y105 0 -12,600 -100.00 0 -100.00
2024-02-14 2023-12-31 13F MERCK COM 58933Y105 12,600 12,600 1,374 0.0185
2022-08-15 2022-06-30 13F MERCK COM 58933Y105 0 -18,000 -100.00 0 -100.00
2022-05-13 2022-03-31 13F MERCK COM 58933Y105 18,000 -71,000 -79.78 1,478 -78.33 0.0178
2022-02-11 2021-12-31 13F MERCK COM 58933Y105 89,000 -151,000 -62.92 6,821 -62.16 0.0765
2021-11-12 2021-09-30 13F MERCK COM 58933Y105 240,000 228,800 2,042.86 18,026 1,969.58 0.2061
2021-08-16 2021-06-30 13F MERCK COM 58933Y105 11,200 11,200 871 0.0114
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
(%)
2026-05-15 2026-03-31 13F MERCK COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2026-02-17 2025-12-31 13F MERCK COM Call 49,500 -79.96 5,210 -74.87 n/a n/a n/a
2025-11-14 2025-09-30 13F MERCK COM Call 247,000 -38.10 20,731 -34.37 n/a n/a n/a
2025-08-14 2025-06-30 13F MERCK COM Call 399,000 280.00 31,585 235.14 n/a n/a n/a
2025-05-15 2025-03-31 13F MERCK COM Call 105,000 9,425 n/a n/a n/a
2024-11-14 2024-09-30 13F MERCK COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2024-08-14 2024-06-30 13F MERCK COM Call 70,000 0.00 8,666 -6.17 n/a n/a n/a
2024-05-15 2024-03-31 13F MERCK COM Call 70,000 9,236 n/a n/a n/a
2022-11-14 2022-09-30 13F MERCK COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2022-08-15 2022-06-30 13F MERCK COM Call 79,900 7,284 n/a n/a n/a
2022-05-13 2022-03-31 13F MERCK COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2022-02-11 2021-12-31 13F MERCK COM Call 229,400 9.50 17,581 11.72 n/a n/a n/a
2021-11-12 2021-09-30 13F MERCK COM Call 209,500 4.75 15,736 1.17 n/a n/a n/a
2021-08-16 2021-06-30 13F MERCK COM Call 200,000 15,554 n/a n/a n/a
2021-02-16 2020-12-31 13F MERCK & CO. COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2020-11-16 2020-09-30 13F MERCK & CO. COM Call 100,000 -50.00 8,295 -46.37 n/a n/a n/a
2020-08-14 2020-06-30 13F MERCK & CO. COM Call 200,000 100.00 15,467 86.46 n/a n/a n/a
2019-08-13 2019-06-30 13F MERCK COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2019-05-14 2019-03-31 13F MERCK COM Call 100,000 8,318 n/a n/a n/a
Disclosed Put 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
(%)
2026-05-15 2026-03-31 13F MERCK COM Put 70,000 -66.48 8,420 -61.69 n/a n/a n/a
2026-02-17 2025-12-31 13F MERCK COM Put 208,800 10.71 21,978 38.85 n/a n/a n/a
2025-11-14 2025-09-30 13F MERCK COM Put 188,600 169.43 15,829 185.67 n/a n/a n/a
2025-08-14 2025-06-30 13F MERCK COM Put 70,000 40.00 5,541 23.46 n/a n/a n/a
2025-05-15 2025-03-31 13F MERCK COM Put 50,000 4,488 n/a n/a n/a
2024-05-15 2024-03-31 13F MERCK COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2024-02-14 2023-12-31 13F MERCK COM Put 100,000 10,902 n/a n/a n/a
2023-05-15 2023-03-31 13F MERCK COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2023-02-14 2022-12-31 13F MERCK COM Put 180,000 20.00 19,971 54.59 n/a n/a n/a
2022-11-14 2022-09-30 13F MERCK COM Put 150,000 233.33 12,919 214.87 n/a n/a n/a
2022-08-15 2022-06-30 13F MERCK COM Put 45,000 4,103 n/a n/a n/a
2022-05-13 2022-03-31 13F MERCK COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2022-02-11 2021-12-31 13F MERCK COM Put 240,000 0.00 18,394 2.04 n/a n/a n/a
2021-11-12 2021-09-30 13F MERCK COM Put 240,000 18,026 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.