Treasury Secretary Timothy Geithner and Federal Reserve Chairman Ben Bernanke showed off the new $100 bill today, set to go into circulation in February of 2011.

The hundred dollar bill is the highest denomination of US currency, and circulation of the bill has jumped to $890 billion from $180 billion in the past quarter century. Interestingly, two out of every three Benjamins circulate outside the US, so the Treasury has to get the word out about the new $100 bill to ensure it will be recognized and honored.

The primary purpose of introducing the new style of $100 bill is to curb counterfeiting:

The new bill’s security features include a blue 3-D Security Ribbon on the front of the note that contains images of bells and 100s, which move and change from one to the other as you tilt the note, according to joint release from the agencies.

Another security feature is the “Bell in the Inkwell” image that changes color from copper to green when the note is tilted, an effect that makes it appear and disappear within the inkwell.

Bernanke estimates that around $6.5 billion is floating around in hundreds right now, and they will remain legal tender.

[WSJ]