THURSDAY, DEC. 31
During the afternoon, the European Commission fixes the euro's value against the 11 EMU members' currencies, posting the rates on the Internet. Banks and stock exchanges plug the data into their computer programs.
JAN. 1 TO JAN. 3
At financial institutions all over Europe, teams of data-processing experts double-check euro software. Many historical data are recalculated. Teams also work around the clock in New York, Tokyo, and other centers abroad.
MONDAY, JAN. 4
When the markets open, European stocks, options, and government bonds trade only in euros. Bank statements show customers' accounts in both local currency and euros. Some big companies adopt the euro for internal accounting.