This image provided by the Treasury Department shows the official signature of Treasury Secretary Jacob Lew that will go on the nation's currency. (TREASURY DEPARTMENT/AP)

Jack Lew was the senior budget adviser to President Obama and President Bill Clinton. He was Obama’s chief of staff. Now he is Treasury secretary.

But his most remarked-upon trait was his unusual signature, a series of eight connected loops that looked more like a doodle than a signature that should grace the U.S. currency. If one had to guess the name, word or, more accurately, sound represented by his old autograph, it would simply be “Oooooooo.”

On Tuesday, that all changed. The Treasury unveiled Lew’s new signature, which will be on the $5 bill this fall and other currency as it is issued over the years. Lew had promised Obama that he would sign his name more legibly as a condition of his nomination.

“Jack assures me that he is going to work to make at least one letter legible in order not to debase our currency should he be confirmed as secretary of the Treasury,” Obama joked in January when announcing Lew’s nomination.

At least one letter, and perhaps two, is legible in the new signature, although one might be hard-pressed to name three. To his credit, the new signature does have three separately identifiable features: a first name, a middle initial (Lew’s is J for Joseph) and a last name.

This combination shows the signatures of Treasury Secretary Jacob Lew from a Sept. 21, 2011 memo posted on the White House website when he was Office of Management and Budget director, top, and as Treasury Secretary on the 2013 annual report for the Financial Stability Oversight Council, bottom. (Uncredited/AP)

On Twitter, where the Treasury Department announced Lew’s new signature, some commentators bemoaned the loss of his old, loopy version, so unique as it was. One observer credibly wrote that his signature now looks like “Paul J Fes.”

Lew is not the first Treasury secretary to change his John Hancock upon arrival at 1500 Pennsylvania Ave. His predecessor, Timothy F. Geithner, changed his signature, too. Lew practiced several variations, stirring attention a few months ago when he signed a public report, leading to speculation that he had settled on a new signature.

But it was still a work in progress. Now that he has selected a signature, the Bureau of Engraving and Printing staff will produce new plates for $5 bills. The new bills will be printed by the bureau, then stored in the vaults of the Federal Reserve, which will decide when to circulate them.

That is expected to happen in the fall — just about the time when Lew and the Treasury will be grappling with a new battle over the budget and the nation’s debt — and might miss the quaint interest of economic and financial geeks in his signature.