Arnold Rothstein and Margaret have an uncomfortable encounter at the brokerage office. What does he think about making a deal with the ex-wife of his rival and sometimes business partner?
Nucky and Arnold are not on the best of terms when he bumps into Margaret. Once he realizes that she is nervous about being discovered, Arnold handles it in a delicate way—and tries to take advantage. He thinks, "Well, I have a little bit of power over her at the moment so perhaps I can use this." That's usually his goal—if he finds an opportunity he tries to take advantage of it.
It's interesting to see their paths cross.
If memory serves, the only time they were together was the New Year's party at the beginning of Season 3 and they didn't interact at all.
Why does Arnold feel it's necessary to hide his identity?
He was very famous at that time for being a gambler of notoriety and success. If the head of a brokerage firm finds out he has Arnold Rothstein in his office, I think there's going to be some kind of ramification.
Even though Margaret fumbles her lines, Arnold invests in the Anaconda Realty Trust. Is he aware that there's a scheme going on?
He invests everywhere and believes there's a possibility of making money here. And when he realizes he has a little bit of power over Margaret, he thinks she might be able to help him out with where the stock will go.