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Merck & Co. (MRK) Institutional Ownership & Insider Trading History

Top MRK institutional shareholders, filing changes, and Form 4 insider activity with filters for buys, sales, option exercises, gifts, and tax withholding.

Last confirmed price
$144.30+0.34%
Oct 2, 2026, 4:02 PM EDT · Prices may be delayed
Market cap · calculated
$356.01B
Oct 2, 2026 · Valuation and sources

Data dates

Prices as of Oct 2, 4:02 PM EDT · Fundamentals checked Oct 4, 8:49 PM EDT · Statement period ended Jun 30, 2026

Ownership read

MRK insider transaction activity: Mixed, sale-heavy.

Blackrock Inc. is the largest institutional holder. 25 sales and 2 purchases appear in the recent Form 4 filings. Use the filters below to separate open-market activity from option exercises, gifts, awards, and tax withholding.

Review insider tradesView institutions

Insider flow

MRK

Purchases17.83K
Sales605.47K

Directional bars ignore awards, gifts, conversions, and tax withholding rows.

Top holder

227.00M

Blackrock Inc.

Insider transaction activity

Mixed, sale-heavy

$73.8M sold / $1.58M bought

Observations shown

88

10 holder / 78 insider

Holder rows
10
Yahoo Finance · Filing dates shown per row
Increased / initiated
9
1 decreased · provider-reported changes
Insider rows
78
Yahoo Finance · Filing dates shown per row

Ownership concentration and transaction activity

Top 10 reported holders
37.12% outstanding
Changes with share-count history
Prior-position data unavailable
New / exited positions
0 / 0 explicitly reported
Largest increase with share-count history
Prior share counts unavailable

These changes cover the holders shown. A holder missing from this list may still own shares. Compare positions from the same reporting quarters.

Net shares sold: 587,639

Sale-code S shares minus purchase-code P shares in this sample. Includes disclosed plans and unknown plan status; excludes grants, gifts, exercises and withholding. This is activity, not sentiment.

  • Purchase / sale; plan unknown: 27
  • Conversion / exercise: 17
  • Other / unclassified: 12
  • Grant: 22

Top 10 institutional holders

Merck & Co. (MRK) institutional ownership

Ranked by reported share count, with position changes and separate position and filing dates where ownership data supplies them.

Merck & Co. (MRK) institutional ownership
#Institution% heldSharesChange %Position / filing date
1
Blackrock Inc.
9.20%227.00M+0.52%Position as of Jun 30, 2026Filing date unknown
2
Vanguard Capital Management LLC
6.54%161.32M+0.21%Position as of Jun 30, 2026Filing date unknown
3
State Street Corporation
4.88%120.41M+0.91%Position as of Jun 30, 2026Filing date unknown
4
Wellington Management Group, LLP
3.50%86.25M+2.29%Position as of Jun 30, 2026Filing date unknown
5
Vanguard Portfolio Management LLC
2.75%67.74M+0.65%Position as of Jun 30, 2026Filing date unknown
6
Geode Capital Management, LLC
2.46%60.74M+1.99%Position as of Jun 30, 2026Filing date unknown
7
Charles Schwab Investment Management, Inc.
2.20%54.37M+9.24%Position as of Jun 30, 2026Filing date unknown
8
Morgan Stanley
1.97%48.64M+2.12%Position as of Jun 30, 2026Filing date unknown
9
FMR, LLC
1.84%45.44M+2.08%Position as of Jun 30, 2026Filing date unknown
10
JPMORGAN CHASE & CO
1.78%43.89M-17.15%Position as of Jun 30, 2026Filing date unknown
Showing 10 of 10 matching institutional rows.

Recent insider transactions

Merck & Co. (MRK) Form 4 filings

Action codes are translated so open-market buys and sales are separate from awards, gifts, conversions, and tax withholding.

Merck & Co. (MRK) Form 4 insider transactions
#Insider% companyActionSharesTransaction date
1
GUINDO CHIRFI
Officer
<0.01%SaleOpen-market or direct sale reported on Form 4.
Transaction context
Classification:
Purchase / sale; plan unknown
10b5-1:
Not reported
Holdings after:
Not reported
Position sold:
Not calculable
Filed:
Not reported

Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership.

10.00KAug 13, 2026
2
DELUCA RICHARD ROBERT JR.
Officer
<0.01%SaleOpen-market or direct sale reported on Form 4.
Transaction context
Classification:
Purchase / sale; plan unknown
10b5-1:
Not reported
Holdings after:
Not reported
Position sold:
Not calculable
Filed:
Not reported

Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership.

45.32KAug 12, 2026
3
ZACHARY JENNIFER L
General Counsel
<0.01%SaleOpen-market or direct sale reported on Form 4.
Transaction context
Classification:
Purchase / sale; plan unknown
10b5-1:
Not reported
Holdings after:
Not reported
Position sold:
Not calculable
Filed:
Not reported

Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership.

80.31KAug 12, 2026
4
ZACHARY JENNIFER L
General Counsel
<0.01%Conversion of Exercise of derivative securityTransaction code reported in the data source. Check the original Form 4 filing for details.
Transaction context
Classification:
Conversion / exercise
10b5-1:
Not reported
Holdings after:
Not reported
Position sold:
Not calculable
Filed:
Not reported

Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership.

54.93KAug 12, 2026
5
DELUCA RICHARD ROBERT JR.
Officer
<0.01%SaleOpen-market or direct sale reported on Form 4.
Transaction context
Classification:
Purchase / sale; plan unknown
10b5-1:
Not reported
Holdings after:
Not reported
Position sold:
Not calculable
Filed:
Not reported

Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership.

6.05KAug 6, 2026
6
GUINDO CHIRFI
Officer
<0.01%SaleOpen-market or direct sale reported on Form 4.
Transaction context
Classification:
Purchase / sale; plan unknown
10b5-1:
Not reported
Holdings after:
Not reported
Position sold:
Not calculable
Filed:
Not reported

Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership.

15.00KAug 6, 2026
7
WILLIAMS DAVID MICHAEL
Chief Technology Officer
<0.01%SaleOpen-market or direct sale reported on Form 4.
Transaction context
Classification:
Purchase / sale; plan unknown
10b5-1:
Not reported
Holdings after:
Not reported
Position sold:
Not calculable
Filed:
Not reported

Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership.

52.85KAug 5, 2026
8
WILLIAMS DAVID MICHAEL
Chief Technology Officer
<0.01%Conversion of Exercise of derivative securityTransaction code reported in the data source. Check the original Form 4 filing for details.
Transaction context
Classification:
Conversion / exercise
10b5-1:
Not reported
Holdings after:
Not reported
Position sold:
Not calculable
Filed:
Not reported

Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership.

52.85KAug 5, 2026
9
MARALDO DAVID R.
Officer
<0.01%SaleOpen-market or direct sale reported on Form 4.
Transaction context
Classification:
Purchase / sale; plan unknown
10b5-1:
Not reported
Holdings after:
Not reported
Position sold:
Not calculable
Filed:
Not reported

Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership.

18.71KAug 5, 2026
10
MARALDO DAVID R.
Officer
<0.01%Conversion of Exercise of derivative securityTransaction code reported in the data source. Check the original Form 4 filing for details.
Transaction context
Classification:
Conversion / exercise
10b5-1:
Not reported
Holdings after:
Not reported
Position sold:
Not calculable
Filed:
Not reported

Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership.

18.71KAug 5, 2026
11
SMART DALTON E. III
Officer
<0.01%Conversion of Exercise of derivative securityTransaction code reported in the data source. Check the original Form 4 filing for details.
Transaction context
Classification:
Conversion / exercise
10b5-1:
Not reported
Holdings after:
Not reported
Position sold:
Not calculable
Filed:
Not reported

Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership.

383May 1, 2026
12
MARALDO DAVID R.
Officer
<0.01%Conversion of Exercise of derivative securityTransaction code reported in the data source. Check the original Form 4 filing for details.
Transaction context
Classification:
Conversion / exercise
10b5-1:
Not reported
Holdings after:
Not reported
Position sold:
Not calculable
Filed:
Not reported

Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership.

552May 1, 2026
Showing 12 of 78 matching Form 4 rows. Percent of company uses current shares outstanding.

Frequently asked

Questions about this quote

Who are the largest MRK shareholders?

Blackrock Inc. is the largest reported institutional holder of MRK, with 227.00 million shares, or about 9.20% of shares outstanding.

What does the institutional filing activity show for MRK?

Merck & Co. has 10 institutional rows on file: 9 increased or initiated positions and 1 reduced them.

What insider transactions are available for MRK?

TECHi shows 78 dated MRK insider transactions through Aug 13, 2026, with transaction types kept separate so administrative actions are not presented as open-market trades.

Are MRK insiders buying or selling?

The displayed MRK activity reads Mixed, sale-heavy: 25 sales and 2 purchases. Other transaction types remain separate.

Who is the most active reported MRK insider?

ZACHARY JENNIFER L has the largest absolute share movement in the displayed MRK filing rows, totaling 418,345 shares. The action labels provide the transaction context.

All data sources

Search the dated figures used for this view. Each entry identifies its units, reporting period and calculation status.

What this page answers

Check who owns the float and whether insiders are active.

Explore Institutional concentration, insider transaction pattern, and float context.

Keep in mind Filings are delayed or transactions are administrative rather than economic.

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