A New Yorker journalist confirmed the signature belongs to Lew. (Twitter)
A swirling autograph dubbed the "world's worst signature" could end up on every new $1 bill in the United States if the frontrunner for the next US Treasury Secretary gets the job.
President Barack Obama is expected to name his current chief of staff and Washington veteran Jack Lew as the successor to Treasury Secretary Timothy Geithner as early as Thursday US time.
Lew is pegged as the favourite to take on the job for his understanding of the complex budget, tax and economic rows consuming Washington.
But while his economic credentials might be solid, the 57-year-old's penmanship has come under fire.
With the Treasury Secretary's "John Hancock" appearing on the lower right-hand spot of every new $1 bill printed during their tenure, a clipping of Lew's loop-de-loop signature is doing the rounds on social media.
The signature was found on a memo and confirmed as belonging to Jacob "Jack" Lew by a New Yorker journalist last September.
It has been called "childish" and the "world's worst signature" by New York magazine, which described the scrawling as looking like a "slinky that has lost its spring".
But even if selected by President Obama for the job and ratified by the US Senate, Lew may choose to alter his signature.
The current Treasury Secretary Tim Geithner also upgraded his autograph before it was printed onto the $1 bill.
Sources: ABC, New York Magazine, AOL