Merck & Co., Inc.
MX ˙ BMV ˙ US58933Y1055
SecurityMX:MRK / Merck & Co., Inc.
InstitutionOmniStar Financial Group, Inc.
Latest Disclosed Ownership21,386 shares
Latest Disclosed Value $ 2,571,779
OmniStar Financial Group, Inc. ownership in MRK / Merck & Co., Inc.

On May 15, 2026 - OmniStar Financial Group, Inc. filed a 13F-HR form disclosing ownership of 21,386 shares of Merck & Co., Inc. (MX:MRK) valued at $2,571,779 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 18,874 shares of Merck & Co., Inc.. This represents a change in shares of 13.31% during the quarter.

OmniStar Financial Group, Inc. 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.

Upgrade to unlock premium data and export to Excel .

Institutional Put/Call Ratios
(Premium Subscription Required)

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)
2026-05-15 2026-03-31 13F MERCK COM 58933Y105 21,386 2,512 13.31 2,572 29.46 1.3336
2026-02-17 2025-12-31 13F MERCK COM 58933Y105 18,874 1,434 8.22 1,987 35.75 1.1644
2025-11-17 2025-09-30 13F MERCK COM 58933Y105 17,440 3,566 25.70 1,464 33.24 0.8866
2025-08-08 2025-06-30 13F MERCK COM 58933Y105 13,874 3,296 31.16 1,098 15.46 0.8219
2025-05-15 2025-03-31 13F MERCK COM 58933Y105 10,578 5,666 115.35 952 94.88 0.7501
2025-02-14 2024-12-31 13F MERCK COM 58933Y105 4,912 -1,731 -26.06 489 -35.28 0.3930
2024-10-17 2024-09-30 13F MERCK COM 58933Y105 6,643 1,539 30.15 755 19.49 0.5653
2024-07-26 2024-06-30 13F MERCK COM 58933Y105 5,104 -454 -8.17 632 -13.92 0.5720
2024-04-23 2024-03-31 13F MERCK COM 58933Y105 5,558 -2,588 -31.77 733 -17.45 0.6716
2024-01-17 2023-12-31 13F MERCK COM 58933Y105 8,146 1,105 15.69 888 22.31 1.1148
2023-11-07 2023-09-30 13F MERCK COM 58933Y105 7,041 -68 -0.96 727 -11.46 0.8626
2023-07-24 2023-06-30 13F MERCK COM 58933Y105 7,109 -5,085 -41.70 820 -36.78 0.9640
2023-05-01 2023-03-31 13F MERCK COM 58933Y105 12,194 -1,354 -9.99 1,297 -13.71 1.6463
2023-01-20 2022-12-31 13F MERCK COM 58933Y105 13,548 -355 -2.55 1,503 25.56 1.7080
2022-11-14 2022-09-30 13F MERCK &CO. INC COM COM 58933Y105 13,903 2,544 22.40 1,197 15.65 1.4264
2022-08-03 2022-06-30 13F MERCK &CO. INC COM COM 58933Y105 11,359 22 0.19 1,035 11.29 1.1468
2022-05-05 2022-03-31 13F MERCK &CO. INC COM COM 58933Y105 11,337 947 9.11 930 16.83 0.9240
2022-02-11 2021-12-31 13F MERCK &CO. INC COM COM 58933Y105 10,390 1,029 10.99 796 13.23 0.8142
2021-11-12 2021-09-30 13F MERCK &CO. INC COM COM 58933Y105 9,361 9,361 703 0.8308
2021-08-17 2021-06-30 13F MERCK & CO. COM 58933Y105 0 -14,805 -100.00 0 -100.00
2021-05-13 2021-03-31 13F MERCK & CO. COM 58933Y105 14,805 -11,729 -44.20 1,141 -47.44 1.4513
2021-02-09 2020-12-31 13F MERCK & CO. COM 58933Y105 26,534 -11,604 -30.43 2,171 -31.38 1.5215
2020-10-22 2020-09-30 13F MERCK & CO. COM 58933Y105 38,138 -438 -1.14 3,164 6.07 2.3864
2020-07-06 2020-06-30 13F MERCK & CO. COM 58933Y105 38,576 9,920 34.62 2,983 35.28 2.4649
2020-04-27 2020-03-31 13F MERCK & CO. COM 58933Y105 28,656 6,444 29.01 2,205 9.16 2.1692
2020-01-13 2019-12-31 13F MERCK COM 58933Y105 22,212 -903 -3.91 2,020 3.80 1.7028
2019-10-11 2019-09-30 13F MERCK COM 58933Y105 23,115 -56 -0.24 1,946 0.15 1.7020
2019-07-30 2019-06-30 13F MERCK COM 58933Y105 23,171 4,439 23.70 1,943 24.71 1.7441
2019-04-12 2019-03-31 13F MERCK COM 58933Y105 18,732 752 4.18 1,558 13.39 1.3702
2019-02-12 2018-12-31 13F MERCK COM 58933Y105 17,980 17,980 -4.01 1,374 -11.81 1.4021
2018-11-16 2018-09-30 13F MERCK & CO INC NEW COM COM 58933Y105 0 -5,994 -100.00 0 -100.00
2018-08-14 2018-06-30 13F MERCK & CO INC NEW COM COM 58933Y105 5,994 595 11.02 363 23.47 0.3456
2018-05-11 2018-03-31 13F MERCK & CO INC NEW COM COM 58933Y105 5,399 -281 -4.95 294 -7.84 0.2809
2018-03-13 2017-12-31 13F MERCK COM 58933Y105 5,680 5,680 319 0.2923
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
(%)
2021-11-12 2021-09-30 13F MERCK &CO. INC COM COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2021-08-17 2021-06-30 13F MERCK &CO. INC COM COM Call 16,809 1,307 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.