Bud leaking info about Bluestar (Dramatic Irony)
When he finally gets a meeting with Gekko, Bud has a hard time impressing the high-powered businessman, and so must resort to giving him some information about Bluestar Airlines, the company for which his father works. We can see in Bud's expression that he feels a little guilty handing over the information without his father knowing, and this accounts for some dramatic irony. While the viewer knows that Bud is giving up information that was told to him casually, Carl and the other employees of Bluestar have no idea.
Bud is given a promotion (Situational Irony)
Bud is a hard worker. He often stays up late into the night looking at the charts so he can be better at his job as a stockbroker. Unfortunately, however, this doesn't pay off and, at the beginning of the film, he is having a hard time ascending the ranks. It is not until he becomes Gordon Gekko's associate that he begins to have success at work, earning himself a promotion and a corner office at his firm. The irony of this success and ascension is that his success is coming by dishonest means, as Gekko has advised him to stop playing by the rules and start learning information about the market through insider trading.
Bud doesn't know about Gekko and Darien (Dramatic Irony)
At the party at Gekko's, where Bud first meets Darien, we see a meaningful touch exchanged between Gekko and Darien, suggesting that they have a romantic history. Then later, they walk down the street together and talk about the fact that they once had an affair. They discuss the fact that Bud has no idea that they have history, and decide that it's best for Bud not to know. This discrepancy between what we as a viewer know about Darien and Gekko's relationship and what Bud knows accounts for some dramatic irony.
Gekko doesn't know that Bud tanked his business (Dramatic Irony)
When Gordon Gekko's Bluestar deal starts to go sour, he becomes livid, cursing whoever is behind its failure and yelling, "When I get a hold of the son of a bitch who leaked this, I'm gonna tear his eyeballs out and I'm gonna suck his fucking skull." What Gekko does not know (but we do), is that Bud is the one who leaked the information, and that his closest business associate is the traitor.
