Considered a classic comedy of the 80s and one of the movies that launched Eddie Murphy's career, can you honestly say you understand the end of 'Trading Places'?

If you've never seen the movie, you're missing out. But long story short, Randolph and Mortimer Duke are rich commodity brokers who are at odds over the battle of Nature vs Nurture. The Dukes create a bet and plan to discredit their top employee, Louis Winthorpe III, and put a con-man, Billy Ray Valentine, in his place to see if their surroundings will cause Valentine to succeed and Winthorpe to turn to crime. While this is going on, the Dukes are also arranging to get a copy of the orange crop report in order to corner the market during the upcoming exchange at New Years. When Winthorpe and Valentine find out about the bet and the Dukes' plan to corner the market, they get the drop of the Dukes during the exchange, getting rich themselves and causing the brothers to lose their vast fortunes.

While the scene on the exchange floor is the climax of the film, not many people really understood what Winthorpe and Valentine did. We gathered that they pulled a fast one on the Dukes, but exactly how? NPR spoke with an expert in orange juice trading and found out how their plan worked.

First, the Dukes got bad information. That much is clear in the movie, with Winthorpe and Valentine intercepting the Dukes' inside man and making the delivery of the orange crop report themselves.

Next, they allowed the Dukes to drive up the price of frozen orange juice. The Dukes believe that the orange crop for the year was bad, due to their false report, and they instruct their trader to buy up as much as possible no matter how high the price goes. The Dukes believe that they'll be able to buy up a massive amount, and then when the crop report announces a bad crop, the cost will skyrocket and they'll be able to sell what they just bought for a huge profit. Supply and demand.

During trading, while the price is going up, Winthorpe yells out "Sell 30 April at 142!", causing traders around him to start buying from him and Valentine like crazy. What Winthorpe announced was his and Valentine's intent to sell at least 30 OJ contracts in April at $1.42 a pound. The other traders, following the Dukes' lead, believe the price will continue to rise and see this as an opportunity to buy a lot at a low price before the value goes up. We are talking about millions of pounds of orange juice here.

While this is going on, the true crop report is broadcast, revealing that the crop was good and there will be no limited supply to drive up the demand. Seeing that the price will not go up due to this, all of the other traders who just bought up OJ futures need to sell them quickly, and the price begins to fall. As the price falls, Winthorpe and Valentine wait for the right time and then offer to start buying, causing all the desperate traders to frantically get rid of their plummeting OJ futures. When the bell rings for the end of trading, the cost for April is 29 cents a pound. In other words, Winthorpe and Valentine arranged contracts to sell millions of pounds of frozen concentrated orange juice for $1.42 a pound, which they ultimately only paid 29 cents a pound for. As for the Dukes, the opposite would be true and result in the Dukes losing millions of dollars.

Knowing exactly what is going on in that scene just makes me appreciate it all that much more. And as we covered in a previous Christmas movie trivia post, when it was finally made illegal to use insider information such as was done in the movie, it was called 'The Eddie Murphy Rule'.

WARNING: NSFW LANGUAGE AT THE END!