The Times Online reports:

Strong demand for the €500 note led the European Central Bank almost to double the value of the bills that it printed to €95 billion last year, from €51.8 billion in 2004. … After the addition of 294 million new €500 notes in the past two years, the denomination now accounts for the most value in circulation of any euro note. …

Drug-traffickers and other criminals — as well as legitimate users — are thought to be conducting business increasingly in euros rather than dollars because it has bigger bills …: a briefcase filled with €500 notes is about six times as valuable as one filled with the highest-denomination American note, the $100 bill. The highest-value British note, the £50, is worth even less.

Technical correction: While the Bank of England’s largest note is £50, two Scottish banks and two Northern Irish banks issue £100 notes.

The value of Federal Reserve dollar notes in circulation ($788 billion, an estimated 50-60% of which is held outside the United States) still exceeds the value of ECB euro notes in circulation (€565 billion), but:

The euro is catching up fast, with supplies growing at about 20 per cent a year, three times as fast as the American currency.