v3.26.1
Fair Value Measurements (Tables)
12 Months Ended
Dec. 31, 2025
EBP 004  
EBP, Investment, Fair Value and NAV [Line Items]  
Schedule of master trust investments measured at fair value
Master Trust investments measured at fair value as of December 31, 2025 are summarized below:
December 31, 2025
Fair Value Measurements Using
(in thousands)Quoted PricesTotal
In ActiveSignificant
Markets forOtherSignificant
Identical ObservableUnobservable
AssetsInputsInputs
(Level 1)(Level 2)(Level 3)
Investments in the Master Trust
Registered investment companies$97,747 $— $— $97,747 
Equity securities2,307,397 — — 2,307,397 
Fixed income securities— 406,994 — 406,994 
Self-directed brokerage accounts459,800 — — 459,800 
Merck common stock907,977 — — 907,977 
Investments measured within the fair value hierarchy$3,772,921 $406,994 $— $4,179,915 
Common/collective trusts measured at NAV practical expedient (1)
$12,677,091 
Master trust investments at fair value$16,857,006 

(1) Certain investments that were measured at net asset value (NAV) per share or its equivalent have not been classified in the fair value hierarchy. The fair value amounts presented in this table also do not include the Master Trust's accrued interest and dividends or other net assets.

The Plan's interests within the Master Trust as specifically identified in Note 6 are leveled in the same manner as the Master Trust investment categories presented above.
Master Trust investments measured at fair value as of December 31, 2024 are summarized below:
December 31, 2024
Fair Value Measurements Using
(in thousands)Quoted PricesTotal
In ActiveSignificant
Markets forOtherSignificant
Identical ObservableUnobservable
AssetsInputsInputs
(Level 1)(Level 2)(Level 3)
Investments in the Master Trust
Registered investment companies$500,106 $— $— $500,106 
Equity securities2,244,340 — — 2,244,340 
Fixed income securities— 386,182 — 386,182 
Self-directed brokerage accounts368,784 — — 368,784 
Merck common stock1,026,831 — — 1,026,831 
Investments measured within the fair value hierarchy$4,140,061$386,182$— $4,526,243
Common/collective trusts measured at NAV practical expedient (1)
$11,107,463
Master trust investments at fair value$15,633,706 

(1) Certain investments that were measured at net asset value (NAV) per share or its equivalent have not been classified in the fair value hierarchy. The fair value amounts presented in this table also do not include the Master Trust's accrued interest and dividends or other net assets.

The Plan's interests within the Master Trust as specifically identified in Note 6 are leveled in the same manner as the Master Trust investment categories presented above.