Merck & Co., Inc.
BG ˙ BUL ˙ US58933Y1055
SecurityBG:6MK / Merck & Co., Inc.
InstitutionMAI Capital Management
Latest Disclosed Ownership335,023 shares
Latest Disclosed Value $ 40,299,941
MAI Capital Management ownership in 6MK / Merck & Co., Inc.

On May 15, 2026 - MAI Capital Management filed a 13F-HR form disclosing ownership of 335,023 shares of Merck & Co., Inc. (BG:6MK) valued at $40,299,941 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 323,491 shares of Merck & Co., Inc.. This represents a change in shares of 3.56% during the quarter.

MAI Capital Management 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)
2026-05-15 2026-03-31 13F MERCK COM 58933Y105 335,023 11,532 3.56 40,300 18.35 0.2274
2026-02-13 2025-12-31 13F MERCK COM 58933Y105 323,491 32,752 11.27 34,051 39.54 0.1958
2025-11-10 2025-09-30 13F MERCK COM 58933Y105 290,739 38,358 15.20 24,402 22.14 0.1520
2025-08-12 2025-06-30 13F MERCK COM 58933Y105 252,381 79,506 45.99 19,978 28.75 0.1380
2025-05-15 2025-03-31 13F MERCK COM 58933Y105 172,875 -7,478 -4.15 15,517 -13.51 0.1170
2025-02-14 2024-12-31 13F MERCK COM 58933Y105 180,353 15,440 9.36 17,941 -4.20 0.1329
2024-11-07 2024-09-30 13F Merck CS 58933Y105 164,913 -17,494 -9.59 18,727 -17.07 0.1783
2024-08-12 2024-06-30 13F Merck CS 58933Y105 182,407 1,666 0.92 22,582 -5.31 0.2212
2024-05-08 2024-03-31 13F Merck CS 58933Y105 180,741 25,836 16.68 23,849 41.22 0.2471
2024-02-09 2023-12-31 13F Merck CS 58933Y105 154,905 536 0.35 16,888 6.26 0.2220
2023-11-14 2023-09-30 13F Merck CS 58933Y105 154,369 -948 -0.61 15,892 -11.33 0.2363
2023-08-02 2023-06-30 13F Merck CS 58933Y105 155,317 2,363 1.54 17,922 10.14 0.2637
2023-05-10 2023-03-31 13F Merck CS 58933Y105 152,954 1,148 0.76 16,273 -3.38 0.2563
2023-02-09 2022-12-31 13F Merck CS 58933Y105 151,806 -5,368 -3.42 16,843 24.42 0.2830
2022-11-15 2022-09-30 13F Merck CS 58933Y105 157,174 26,249 20.05 13,536 13.40 0.2543
2022-07-19 2022-06-30 13F Merck CS 58933Y105 130,925 -1,060 -0.80 11,936 10.22 0.2279
2022-05-10 2022-03-31 13F Merck CS 58933Y105 131,985 -8,102 -5.78 10,829 0.87 0.1820
2022-02-11 2021-12-31 13F Merck CS 58933Y105 140,087 231 0.17 10,736 2.20 0.1730
2021-11-12 2021-09-30 13F Merck CS 58933Y105 139,856 -39 -0.03 10,505 -3.45 0.2023
2021-07-19 2021-06-30 13F Merck CS 58933Y105 139,895 -5,880 -4.03 10,880 -3.19 0.2160
2021-05-10 2021-03-31 13F Merck CS 58933Y105 145,775 -21,338 -12.77 11,238 -17.79 0.2512
2021-02-16 2020-12-31 13F Merck CS 58933Y105 167,113 -577 -0.34 13,670 -1.73 0.3418
2020-10-26 2020-09-30 13F Merck CS 58933Y105 167,690 -12,109 -6.73 13,910 0.04 0.4027
2020-07-27 2020-06-30 13F Merck CS 58933Y105 179,799 5,854 3.37 13,904 3.89 0.4365
2020-04-16 2020-03-31 13F Merck CS 58933Y105 173,945 -3,141 -1.77 13,383 -16.91 0.5462
2020-02-03 2019-12-31 13F Merck CS 58933Y105 177,086 82,531 87.28 16,106 102.34 0.5220
2019-10-29 2019-09-30 13F Merck CS 58933Y105 94,555 4,362 4.84 7,960 5.25 0.3547
2019-08-15 2019-06-30 13F Merck CS 58933Y105 90,193 4,682 5.48 7,563 6.34 0.3417
2019-04-29 2019-03-31 13F Merck CS 58933Y105 85,511 639 0.75 7,112 9.67 0.3642
2019-01-30 2018-12-31 13F Merck CS 58933Y105 84,872 7,383 9.53 6,485 17.97 0.3780
2018-10-12 2018-09-30 13F Merck CS 58933Y105 77,489 980 1.28 5,497 18.37 0.2808
2018-08-16 2018-06-30 13F Merck CS 58933Y105 76,509 1,725 2.31 4,644 14.02 0.2505
2018-04-17 2018-03-31 13F Merck CS 58933Y105 74,784 3,923 5.54 4,073 2.16 0.2312
2018-01-30 2017-12-31 13F Merck CS 58933Y105 70,861 13,207 22.91 3,987 7.99 0.2265
2017-10-12 2017-09-30 13F Merck CS 58933Y105 57,654 1,816 3.25 3,692 3.16 0.2241
2017-08-07 2017-06-30 13F Merck CS 58933Y105 55,838 1,281 2.35 3,579 3.23 0.2306
2017-05-11 2017-03-31 13F Merck CS 58933Y105 54,557 -1,885 -3.34 3,467 4.33 0.2333
2017-01-31 2016-12-31 13F Merck CS 58933Y105 56,442 -4,054 -6.70 3,323 -12.00 0.2416
2016-10-18 2016-09-30 13F Merck CS 58933Y105 60,496 2,917 5.07 3,776 13.84 0.2848
2016-07-14 2016-06-30 13F Merck CS 58933Y105 57,579 -4,385 -7.08 3,317 1.16 0.2556
2016-04-08 2016-03-31 13F Merck CS 58933Y105 61,964 759 1.24 3,279 1.42 0.2508
2016-01-27 2015-12-31 13F Merck CS 58933Y105 61,205 9,401 18.15 3,233 26.34 0.2465
2015-10-28 2015-09-30 13F Merck CS 58933Y105 51,804 39,830 332.64 2,559 275.22 0.1936
2015-07-09 2015-06-30 13F Merck CS 58933Y105 11,974 801 7.17 682 6.23 0.0449
2015-04-30 2015-03-31 13F Merck CS 58933Y105 11,173 1,255 12.65 642 14.03 0.0430
2015-01-20 2014-12-31 13F Merck CS 58933Y105 9,918 -200 -1.98 563 -6.17 0.0395
2014-10-16 2014-09-30 13F/A-1 Merck CS 58933Y105 10,118 -102 -1.00 600 1.52 0.0578
2014-10-16 2014-09-30 13F Merck COM 58933Y105 10,220 591
2014-07-28 2014-06-30 13F Merck COM 58933Y105 10,220 -3,408 -25.01 591 -23.64 0.0568
2014-04-28 2014-03-31 13F Merck COM 58933Y105 13,628 -1,125 -7.63 774 4.88 0.0779
2014-02-06 2013-12-31 13F Merck COM 58933Y105 14,753 -727 -4.70 738 0.14 0.0782
2013-10-28 2013-09-30 13F Merck COM 58933Y105 15,480 559 3.75 737 6.35 0.0958
2013-08-01 2013-06-30 13F Merck COM 58933Y105 14,921 14,921 693 0.0903
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
(%)
2023-11-14 2023-09-30 13F Merck & CS Call 0 -100.00 0 -100.00 n/a n/a n/a
2023-08-02 2023-06-30 13F Merck & CS Call 3,900 0.00 450 8.70 n/a n/a n/a
2023-05-10 2023-03-31 13F Merck & CS Call 3,900 415 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 PUT Put 1,323 215.75 n/a n/a n/a
2025-11-10 2025-09-30 13F MERCK PUT Put 420 6.08 n/a n/a n/a
2025-08-12 2025-06-30 13F MERCK PUT Put 396 -11.83 n/a n/a n/a
2025-05-15 2025-03-31 13F MERCK PUT Put 449 -19.57 n/a n/a n/a
2025-02-14 2024-12-31 13F MERCK PUT Put 557 -12.28 n/a n/a n/a
2024-11-07 2024-09-30 13F Merck & CS Put 5,600 0.00 636 -8.37 n/a n/a n/a
2024-08-12 2024-06-30 13F Merck & CS Put 5,600 -49.09 693 -52.24 n/a n/a n/a
2024-05-08 2024-03-31 13F Merck & CS Put 11,000 37.50 1,451 66.40 n/a n/a n/a
2024-02-09 2023-12-31 13F Merck & CS Put 8,000 -23.81 872 -19.26 n/a n/a n/a
2023-11-14 2023-09-30 13F Merck & CS Put 10,500 250.00 1,081 212.14 n/a n/a n/a
2023-08-02 2023-06-30 13F Merck & CS Put 3,000 -62.50 346 -59.34 n/a n/a n/a
2023-05-10 2023-03-31 13F Merck & CS Put 8,000 851 n/a n/a n/a
2023-02-09 2022-12-31 13F Merck CS Put 0 -100.00 0 -100.00 n/a n/a n/a
2022-11-15 2022-09-30 13F Merck CS Put 21,000 -32.26 1,809 -36.01 n/a n/a n/a
2022-07-19 2022-06-30 13F Merck & CS Put 31,000 210.00 2,827 244.34 n/a n/a n/a
2022-05-10 2022-03-31 13F Merck & CS Put 10,000 -78.72 821 -77.21 n/a n/a n/a
2022-05-10 2022-03-31 13F Merck & CS Put 34,000 2,790 n/a n/a n/a
2022-02-11 2021-12-31 13F Merck & CS Put 47,000 -9.62 3,602 -7.78 n/a n/a n/a
2021-11-12 2021-09-30 13F Merck & CS Put 52,000 -1.89 3,906 -5.24 n/a n/a n/a
2021-07-19 2021-06-30 13F Merck & CS Put 53,000 20.45 4,122 21.52 n/a n/a n/a
2021-05-10 2021-03-31 13F Merck & CS Put 44,000 51.72 3,392 43.00 n/a n/a n/a
2021-02-16 2020-12-31 13F Merck & CS Put 29,000 -14.71 2,372 -15.89 n/a n/a n/a
2020-10-26 2020-09-30 13F Merck & CS Put 34,000 -42.86 2,820 -38.71 n/a n/a n/a
2020-07-27 2020-06-30 13F Merck & CS Put 59,500 -4.80 4,601 -4.31 n/a n/a n/a
2020-04-16 2020-03-31 13F Merck & CS Put 62,500 0.00 4,808 -15.41 n/a n/a n/a
2020-02-03 2019-12-31 13F Merck & CS Put 62,500 5,684 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.