Warning: Wikipedia contains spoilers
The story involves a young stock broker, Bud Fox (played by Charlie Sheen), who is desperate to get to "the top". He settles on a plan to become involved with his hero, the extremely successful businessman Gordon Gekko (played by Michael Douglas).
After succeeding in meeting Gekko, Fox gives him a stock tip based on insider information he happened to come across while talking to his father, Carl (played by Martin Sheen, Charlie's real-life father). Carl is a maintenance chief at a small airline, Bluestar and learns that they will soon be cleared of a safety concern after a previous crash.
Carl's character represents the working class in the movie, he is the union leader for the maintenance workers at Bluestar. The conflict between Gekko's relentless pursuit of wealth and Carl Fox's leftward leanings form the basis of the film's subtext. This subtext could be described as the concept of the "two fathers," one good and one evil, battling for control over the morals of the "son." In Wall Street the hard-working Carl Fox and the cutthroat businessman Gordon Gekko represent the fathers. The fact that Bud and Carl Fox are played by real life father and son Martin and Charlie Sheen make the conflict all the more interesting on screen. The producers of the film use Carl as their voice in the film, a voice of reason amid the destructive actions brought about by the unrestrained appetite for money of Gekko.
Gekko uses the information Bud reveals to him about Bluestar to make a small profit when the stock jumps after the verdict on the crash is released. Fox quickly learns that this is the "secret" to Gekko's success—insider information—but the illegalities and ethical conflict involved bother him only slightly as he is quickly admitted into Gekko's "inner circle". Fox quickly becomes very wealthy and gets all the perks—the fancy apartment, the (as it turns out, streetwise and wary) trophy blonde (Darryl Hannah), the cars.
However this changes when Gekko decides to do a corporate raid on Fox's father's company. At this point he must choose between the rich insider's lifestyle offered by working outside the law, or his father's more traditional blue collar values of fair play and hard work. He chooses to try and preserve the latter by utilising what he has learnt from Gekko. To achieve this Bud uses a business rival to break the deal, being indicted for insider trading in the process. He gets his last revenge by turning state's evidence against Gekko, going to jail himself in the process.
The movie is significant in terms of reflecting the public's general malaise with the current state of affairs in the "big business" world both in the late 1980s and in the wake of the late 1990s post-internet bubble scandals.
Gekko clearly represents Donald Trump whose dealings were being reported on daily. Stone was not trying to point out illegal dealings, but to illustrate the corrupt lifestyle of everyone involved in the financial system, legal or no. The system values The Deal more than what the deal representes, people and goods—a system Stone apparently believes is without value.
Perhaps the most remembered scene in the movie is a speech by Gekko to a shareholders' meeting of Teldar Paper, a company he is planning to take over. Stone uses this scene to give Gekko, and by extension, the Wall Street raiders he personifies, the chance to justify their actions, which he memorably does, pointing out the slothfulness and waste that corporate America accumulated through the postwar years and from which he sees himself as a "liberator":