Beginning in 2003 the US Federal Reserve began redesigning the US’s currency under a program called the “New Color of Money”. This program introduced subtle hints of color, watermarks and various other features to US bank notes.
The new $10, $20, and $50 notes have been in circulation for years. However, the Federal Reserve understood that it had to take its time making the $100 note the most secure bill of the lot. According to the Federal Reserve at least half of its $100 notes in circulation actual live outside the United States. It is therefore unsurprising that the $100 bill is the most commonly counterfeited currency on the planet.
Over the last decade the US government has spared no expense engineering a bill that will be extremely difficult to counterfeit. Among the new features is a 3D ribbon that imparts a number of visual effects to the note as it is moved in different directions. The face of the $100 note also contains a color changing copper inkwell feature. Embedded in this inkwell is an image of a bell. As the bill is tilted the burnt-orange inkwell transforms to a green color making the interior bell appear and disappear.
The Fed is pretty certain it’s created the safest $100 bill yet, having also added raised printing, watermarks, and serial numbers.
Although the new $100 notes begin circulating today, have no fear, your old $100 are still considered legal tender.