Noticably absent from the beginning of Season Four was Ness nemesis, Frank Nitti. It was almost as though he never existed at all as I believe he was only mentioned once in Elegy. The reason for his absence was that he had been dropped as a recurring character at the end of Season Three as the show tried to purge itself of Italian villains and become kinder and gentler. But as we found out at the end of Season One it's hard to keep a good Enfocer down and when the ratings for Season Four nosedived Nitti was brought back for three mid-season episodes beginning with The Speculator.
Of the three Nitti episodes in the show's final season, The Speculator is easily the weakest. Since the rest of the show had been watered down I guess the producers felt they had to water down the Enforcer a bit too. Here Nitti, who saw through a sharp operator like Walter Trager in Season Three's Jigsaw, is almost a buffoon who is completely taken in by the obviously phony Leo Stazak. Sure, they gave Bruce Gordon some of his best one-liners of the series in this episode but they also dumbed down the character considerably and Telly Savalas is less than impressive as Leo Stazak. Interestingly enough, Savalas' three Untouchables appearances were all with Gordon.
Still, even a dumbed down Nitti is better than no Nitti at all and The Speculator is a decent episode by Season Four standards (which are admittedly lower). The best scene is when Nitti informs Ness in the steamroom that he got wiped out in the stock market. For a brief moment Nitti shows some vulnerability. He's not a gangster but rather another unfortunate investor who got wiped out in the crash.