Julius Wilford "Nicky" Arnstein[1] (born Arndstein;[2] July 1, 1879 – October 2, 1965) was an American professional gambler and con artist.

[5] Nicky was short for nickel plate, a sobriquet bestowed in the 1890s when, as a boy, Arnstein rode a gleaming nickel-plated bicycle in the then-popular bike racing craze.

[1] He gambled cards on transatlantic liners and in European casinos, and eventually fell in with Arnold Rothstein, a loan shark, bookmaker, fence, Wall Street swindler, real estate speculator, and labor racketeer, who was best known for fixing the 1919 World Series.

Arnstein was arrested multiple times between 1909 and 1912 for various cons in London, Paris and Monte Carlo,[1] but wasn't convicted.

[8] On May 16, 1924, having been convicted of conspiracy to sell $5 million of stolen securities, Arnstein entered Leavenworth prison, where he remained for almost two years.

[11] Arnstein, using the alias Jules Arnold, was briefly arrested in New York City on April 5, 1929 for allegedly swindling $32,000 from a Massachusetts man,[12] but was released two days later when it was shown he only resembled the actual culprit.

[14] Arnstein said his character as portrayed by Tyrone Power depicted him as "a coward, weakling, confidence man, swindler to say nothing of a faithless deceitful husband.