Lamborghini
Jordan drives his Lamborghini from the country club to home. And he's surprised in his narration that he makes it safely as he's so high he can't walk or even speak. But then we see that Jordan's Lamborghini is trashed as the cops arrest him at his home. This is a symbol that when one is numbed up by the high of drugs their reality is altered, many times in ways where they believe they are safe when if truth they've caused great damage.
Boat
Agent Denham accepts Jordan's invitation to meet him on his yacht. But Denham calls Jordan's multi-million dollar yacht a "boat." It's a symbol that Jordan's wealth won't buy this man who is out to prove that Jordan and his firm are thieves.
FBI
Agent Denham works for the FBI and is the point person trying to bring Jordan and his cronies down throughout the film. Denham is a symbol of morality in contrast to Jordan's lack of it. He's willing to go to any lengths to ensure that Jordan doesn't continue breaking the law.
Martini Lunch
Jordan is taken to lunch by Mark Hanna on his first day on Wall Street. There Hanna orders martinis from the waiter with the intention of passing out at lunch. This is shortly after he's done cocaine at the table. These are symbols of Hanna's belief that the only way to be a stockbroker is to be drugged up on everything from drugs, booze and women. Essentially, Hanna knows what he's doing doesn't have great moral purpose and thus he medicates any way he can.
Incomprehension
Mark Hanna tells Jordan that there is no one in the world who knows how stocks work - why they go up or down. This is a symbol that the stock market is a volatile way to earn money, and Hanna goes on to explain that the only point is to make money as a broker. Not to make your clients money.
