It is 1985, and Bud Fox is working as a junior stockbroker at Jackson Steinem & Co. His dream is to work with his hero, Gordon Gekko, a legendary player on Wall Street. Fox's dream becomes an obsession. He bombards Gekko's office with calls, calling fifty-nine days in a row in an attempt to get an appointment - to no avail. Thinking outside the box, Bud makes a personal visit to Gekko on his birthday, taking him a box of Gekko's favorite contraband Cuban cigars. Gekko is impressed by Fox's boldness and audacity and finally grants him am interview. However when Fox pitches him stock picks he fails to impress and sending his opportunity slipping away, Fox provides him with some inside information about Bluestar Airlines. Fox's father works at Bluestar and is union leader for the airline's workforce. The information was learned during a casual conversation but Bud hopes it will swing the pendulum in his favor. Gekko is intrigued and tells Bud he will look at the company but tempers Bud's reaction by telling him that he looks at a hundred deals every day but only chooses one. Dejected, Fox returns to his office. Gekko subsequently places an order for Bluestar stock and becomes one of Bud's clients. He gives him some capital to manage but the other stocks Bud selects lose money, giving every indication that he can only pick winning stock with the use of inside information.
Surprisingly, Gekko gives Fox a second chance and tasks him with spying on British CEO Sir Lawrence Wildman to find out what his next move will be. Bud leaens that Wildman is making a bid on a steel company and as a result of Bud's spying Gekko makes an enormous amount of money. Wildman is forced to buy Gekko's shares from him at an inflated price in order to complete his planned take-over.
Foxis becoming wealthy and enjoys all the perks that Gekko promised and delivered on, including a penthouse on Manhattan's Upoer East Side, and a beautiful trophy girlfriend to live in it with him. Darien is a successful interior designer with a clutch of wealthy clients. Because Fox is making such large commission fees from his trades with Gekko, he is promoted to Senior Stockbroker, a position that also affords him the coveted corner office. He continues to maximize inside information and he uses friends as straw buyers to provide both him and Gekko with more income. Although he is unaware of it some of his trades are attracting the attention of the Securities and Exchange Commission.
Bud has a new idea to pitch to Gekko which involves purchasing Bluestar Airlines and expanding it, making Fox president in the process, the expansion possible using savings achieved by union concessions and the overfunded pension fund. Bud does not manage to persuade his father to support the deal but does succeed in getting the unions to push for it. However Fox soon learns that Gekko's plan for the company diverges from his own; Gekko will dissolve the company, sell off the company's assets and access the funds in the pension plan, leaving Bud's father and the entire Bluestar staff without a job. Although this would make Bud an extremely rich man, Gekko's deceit angers him. He is consumed by the guilt of being the conduit that set this plan in motion and resents being an accessory to the destruction of Bluestar, his guilt exacerbated when his father suffers a heart attack. Bud resolves to disrupt Gekko's plan and becomes so single-minded about this goal that when Darien, Gekko's former lover, refuses to go along with it Bud breaks up with her.
Bud devises a plan to artificially drive up Bluestar stock before manipulating it back down again. He and the union presidents secretly meet with Sir Lawrence Wildman who is only too happy to avenge the steel company deal. They arrange for Wildman to purchase controlling interest in Bluestar at a very significant discount. Gekko realizes the value of his Bluestar stock is plummeting and on Bud's advice dumps his remaining interest in the company. However when Gekko learns on the evening news that Wildman is buying the company he realizes that the entire scheme was engineered by Bud. Bud goes to work the next day only to be arrested for insider trading.
Sometime later Bud confronts Gekko whilst in Central Park. Gekko berates him for his role in the Bluestar deal and accuses him of ingratitude. Following their confrontation it is revealed that Bud was wearing a wire and has recorded Gekko complaining that he did not appreciate their illicit deals. Bud turns the recording over to authorities who tell him that he may get a lighter sentence if he helps them build a case against Gekko. Subsequently, Bud's parents drive him down FDR Drive to the Supreme Court Building Downtown where he will have to answer for the crimes he committed under Gekko's influence. Bus's father tells him that he did the right thing in saving Bluestar Airline and the livelihood of its employees. The film ends as Bud climbs the steps of the Courthouse, knowing he will likely be ruined, but knowing also that his conscience is clear.