[fedreserved]

One if their main duties is to go after counterfeiting of the currency. In fact it's what they were founded to do

https://www.secretservice.gov/about/history

We are one of America’s oldest federal law enforcement agencies, originally created in 1865 to stamp out rampant counterfeiting in order to stabilize America's young financial system. By the end of the Civil War, nearly one-third of all currency in circulation was counterfeit. As a result, the country’s financial stability was in jeopardy. To address this concern, the Secret Service was established in 1865 as a bureau in the Treasury Department to suppress widespread counterfeiting.

[GravitasFailure]

Another bit of trivia: Lincoln signed the bill creating the secret service on the day of his assassination, which is why the Treasury is tasked with executive protection.

[snowwrestler]

Well, they were. Secret Service moved from Treasury to DHS after 9/11.

[JohnJamesRambo]

Will you ever address this counterfeiting?

https://fred.stlouisfed.org/series/M2SL