v3.26.1
Master Trust (Tables)
12 Months Ended
Dec. 31, 2025
EBP 061  
EBP, Master Trust [Line Items]  
Schedule of master trust net assets
The net assets of the Master Trust and the Plan's interest are as follows:

2025
(in thousands)Master TrustPuerto Rico
Registered investment companies (mutual funds)$97,747 $1,674 
Common/collective trusts12,677,091 171,262 
Equity securities2,307,397 33,498 
Fixed income securities406,994 7,217 
Self-directed brokerage accounts459,800 1,048 
Merck common stock907,977 29,306 
Accrued interest and dividends15,877 389 
Other net assets8,648 143 
$16,881,531 $244,537 
2024
(in thousands)Master TrustPuerto Rico
Registered investment companies (mutual funds)$500,106 $7,602 
Common/collective trusts11,107,463 151,225 
Equity securities2,244,340 32,895 
Fixed income securities386,182 6,655 
Self-directed brokerage accounts368,784 431 
Merck common stock1,026,831 29,511 
Accrued interest and dividends17,180 388 
Other net assets4,994 70 
$15,655,880$228,777
Total investment income (loss) of the Master Trust for the year ended December 31, 2025, is as follows:
2025
(in thousands)Master Trust
Investment income
    Net appreciation$2,354,281 
    Interest and dividends157,490 
        Total investment income$2,511,771