The Dow Jones Industrial Average is made up of 30 US companies:-

MSFT Microsoft
AAPL Apple
JNJ Johnson & Johnson
V Visa
WMT Walmart
PG Procter & Gamble
JPM JPMorgan Chase
UNH UnitedHealth
INTC Intel
HD Home Depot
VZ Verizon
MRK Merck & Co
KO Coca-Cola
DIS Walt Disney
CSCO Cisco Systems
CVX Chevron
CRM Salesforce.com
AMGN Amgen
NKE Nike
MCD McDonalds
IBM IBM
HON Honeywell International
MMM 3M
BA Boeing
AXP American Express
GS Goldman Sachs
CAT Caterpillar
GE General Electric
DWDP DuPont de Nemours, Inc.
TRV Travelers Companies