Though the goals were clear, they were far from easy to achieve. The new $100 bill had to, according to Federal Reserve Board Governor Jerome H. Powell, be "easier to authenticate, but harder to replicate." It took 10 years and the combined efforts of the Federal Reserve, U.S. Department of the Treasury, U.S. Bureau of Engraving and Printing, and the Secret Service to create a note that seemed to meet those objectives. Now that the bill has been in circulation since October 8, it is simply a matter of waiting to see if they were correct.

"The U.S. redesigns its currency to stay ahead of counterfeiters," says Carol Riggs, a spokesperson for the Bureau of Engraving and Printing, the government agency that produces paper currency. To that end, the new bill has a blue ribbon woven into it (as opposed to printed onto the paper). This ribbon, explains Riggs, is "made of thousands of micro-lenses, which creates motion." When the note is tilted, the bells and 100s on the ribbon move either back and forth or up and down. On the front of the note there is a bell inside a copper inkwell, printed with color-shifting ink that turns green when you move the bill. "[These changes] are technologically advanced, but also quick and easy to use in day-to-day transactions," says Riggs.
Although the average person spends more time with 1s, 10s, and 20s, the $100 bill is the most popular denomination for forgers--explaining why it was updated in 1996 and again less than 20 years later. Notes also have a healthy shelf life of approximately eight years--$100 bills last longer than those of lesser value because they aren't used as frequently. In addition, savvy counterfeiters have taken advantage of improvements in technology to make forgeries easier, including a ring of North Korean forgers who use presses or ink from Switzerland to create bills of such superior quality that they are called Supernotes. So although the Secret Service says less than 0.01% of the U.S. dollars being used are fake, that still amounts to nearly $100 million worth of counterfeit bills in circulation.
While making the bills harder to replicate will go a long way in getting them out of circulation, there is a second, equally important step: Shoppers, merchants, and bankers need to notice if they have fake money and not pass it along. It's the monetary equivalent of a falling tree in a forest--if a bill is forged but no one takes the time to examine it, does all of this anti-counterfeiting really matter? "People have so many things vying for our attention, we are unlikely to remember to be vigilant [to examine money]," says Matthew G. Nagler, a behavioral economist and associate professor of economics at the City College of New York. There is also little incentive to turn in a fake bill beyond civic do-goodery, as there is no reimbursement--one fake for one real--for the conscientious consumers or business people who sound the alarm that they have received forged money.
Those obstacles aside, experts, including Nagler, agree that this new bill is on track to turn citizens into more vigilant spenders. "They seem to have grasped the idea of ease, which a behavioral economist might refer to as 'low cognitive cost,'" he says. The flipside, the higher costs of a market flooded with more fake bills, is an alternative that the government will continue to fight.