Merck & Co., Inc.
BG ˙ BUL ˙ US58933Y1055
SecurityBG:6MK / Merck & Co., Inc.
InstitutionParallel Advisors, LLC
Latest Disclosed Ownership52,201 shares
Latest Disclosed Value $ 5,494,729
Parallel Advisors, LLC ownership in 6MK / Merck & Co., Inc.

On February 11, 2026 - Parallel Advisors, LLC filed a 13F-HR form disclosing ownership of 52,201 shares of Merck & Co., Inc. (BG:6MK) valued at $5,494,729 USD as of December 31, 2025. The entity filed a previous 13F-HR on November 13, 2025 disclosing 48,022 shares of Merck & Co., Inc.. This represents a change in shares of 8.70% during the quarter.

Parallel Advisors, 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 .

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)
2026-02-11 2025-12-31 13F MERCK Stock 58933Y105 52,201 4,179 8.70 5,495 36.33 0.1005
2025-11-13 2025-09-30 13F MERCK Stock 58933Y105 48,022 1,036 2.20 4,031 8.36 0.0738
2025-07-08 2025-06-30 13F MERCK Stock 58933Y105 46,986 -7,640 -13.99 3,719 -24.13 0.0743
2025-04-08 2025-03-31 13F MERCK Stock 58933Y105 54,626 -4,299 -7.30 4,903 -16.36 0.1106
2025-02-10 2024-12-31 13F MERCK Stock 58933Y105 58,925 -753 -1.26 5,862 -13.52 0.1318
2024-11-13 2024-09-30 13F MERCK Stock 58933Y105 59,678 -1,105 -1.82 6,777 -9.93 0.1593
2024-08-08 2024-06-30 13F MERCK Stock 58933Y105 60,783 2,248 3.84 7,525 -2.58 0.1928
2024-05-06 2024-03-31 13F MERCK Stock 58933Y105 58,535 4,896 9.13 7,724 32.08 0.2093
2024-02-12 2023-12-31 13F MERCK Stock 58933Y105 53,639 -530 -0.98 5,848 4.86 0.1735
2024-05-20 2023-09-30 13F/A-1 MERCK Stock 58933Y105 54,169 -1,992 -3.55 5,577 -13.95 0.1858
2023-11-14 2023-09-30 13F MERCK Stock 58933Y105 54,169 -1,992 5,577 0.1858
2024-05-20 2023-06-30 13F/A-1 MERCK Stock 58933Y105 56,161 670 1.21 6,480 9.77 0.2087
2023-08-04 2023-06-30 13F MERCK Stock 58933Y105 56,161 670 6,480 0.2087
2024-05-20 2023-03-31 13F/A-1 MERCK Stock 58933Y105 55,491 2,996 5.71 5,904 1.36 0.1991
2023-04-25 2023-03-31 13F MERCK Stock 58933Y105 55,491 2,996 5,904 0.1991
2023-02-06 2022-12-31 13F MERCK Stock 58933Y105 52,495 3,250 6.60 5,824 37.33 0.2526
2022-11-10 2022-09-30 13F MERCK Stock 58933Y105 49,245 9,242 23.10 4,241 16.29 0.1952
2022-08-01 2022-06-30 13F MERCK Stock 58933Y105 40,003 1,788 4.68 3,647 15.81 0.1674
2022-04-28 2022-03-31 13F MERCK Stock 58933Y105 38,215 823 2.20 3,149 9.87 0.1249
2022-01-20 2021-12-31 13F MERCK Stock 58933Y105 37,392 -3,933 -9.52 2,866 -7.67 0.1064
2021-11-02 2021-09-30 13F/A-1 MERCK Stock 58933Y105 41,325 3,071 8.03 3,104 4.34 0.1252
2021-08-06 2021-06-30 13F MERCK Stock 58933Y105 38,254 7,825 25.72 2,975 26.81 0.1260
2021-04-23 2021-03-31 13F MERCK Stock 58933Y105 30,429 -1,522 -4.76 2,346 -10.25 0.1107
2021-02-02 2020-12-31 13F MERCK Stock 58933Y105 31,951 -4,679 -12.77 2,614 -13.96 0.1419
2020-10-27 2020-09-30 13F MERCK Stock 58933Y105 36,630 -630 -1.69 3,038 5.45 0.1880
2020-07-16 2020-06-30 13F MERCK Stock 58933Y105 37,260 2,963 8.64 2,881 9.21 0.1880
2020-04-27 2020-03-31 13F MERCK Stock 58933Y105 34,297 814 2.43 2,638 -13.37 0.2136
2020-01-30 2019-12-31 13F MERCK Stock 58933Y105 33,483 1,250 3.88 3,045 12.24 0.2284
2019-11-01 2019-09-30 13F MERCK Stock 58933Y105 32,233 1,437 4.67 2,713 5.07 0.2323
2019-08-05 2019-06-30 13F MERCK Stock 58933Y105 30,796 -3,042 -8.99 2,582 -8.24 0.2519
2019-05-01 2019-03-31 13F MERCK Stock 58933Y105 33,838 -410 -1.20 2,814 7.61 0.3159
2019-02-05 2018-12-31 13F MERCK Stock 58933Y105 34,248 3,173 10.21 2,615 18.65 0.3646
2018-11-01 2018-09-30 13F MERCK Stock 58933Y105 31,075 1,263 4.24 2,204 21.84 0.2738
2018-07-30 2018-06-30 13F MERCK Stock 58933Y105 29,812 1,596 5.66 1,809 17.70 0.2587
2018-05-08 2018-03-31 13F MERCK Stock 58933Y105 28,216 -715 -2.47 1,537 -5.59 0.2400
2018-02-13 2017-12-31 13F MERCK & CO INC COM Stock 58933Y105 28,931 65 0.23 1,628 2.33 0.2664
2017-11-15 2017-09-30 13F/A-1 MERCK & CO INC COM Stock 58933Y105 28,866 -1,420 -4.69 1,591 -17.78 0.2736
2017-08-07 2017-06-30 13F MERCK & CO INC COM Stock 58933Y105 30,286 1,490 5.17 1,935 5.62 0.3649
2017-05-12 2017-03-31 13F/A-1 MERCK & CO INC COM Stock 58933Y105 28,796 2,625 10.03 1,832 18.88 0.3642
2017-05-12 2017-03-31 13F MERCK & CO INC COM Stock 58933Y105 28,796 1,832
2017-02-14 2016-12-31 13F MERCK & CO INC COM Stock 58933Y105 26,171 26,171 1,541 0.3619
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
(%)
2022-01-19 2021-12-31 13F MERCK Stock Call 0 -100.00 0 -100.00 n/a n/a n/a
2021-10-22 2021-09-30 13F MERCK Stock Call 38,254 2,975 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.