They witness an encounter between their managing director—the well-mannered and educated Louis Winthorpe III, engaged to the Dukes' grandniece Penelope Witherspoon—and poor black street hustler Billy Ray Valentine.

Holding opposing views on the issue of nature versus nurture, the Dukes make a wager and agree to conduct an experiment to observe the results of switching the lives of Valentine and Winthorpe, two people in contrasting social strata.

Watching a television news broadcast, they learn that Beeks is transporting a secret United States Department of Agriculture (USDA) report on orange crop forecasts.

Remembering large payments made to Beeks by the Dukes, Winthorpe and Valentine decide to foil the brothers' plan to obtain the report early and use it to corner the market on frozen concentrated orange juice.

On New Year's Eve, the four board Beeks' train in disguise, intending to switch the original report with a forgery that predicts low orange crop yields.

As the traders frantically sell their futures, Valentine and Winthorpe buy at the lower price from everyone except the Dukes, fulfilling the contracts they had short-sold earlier and turning an immense profit.

When the Dukes prove unable to pay the $394 million required to satisfy their margin call, the exchange manager orders their seats sold and their corporate and personal assets confiscated, effectively bankrupting them.

As well as the main cast, Trading Places features Robert Curtis-Brown as Todd, Winthorpe's romantic rival for Penelope; Alfred Drake as the Securities Exchange manager;[6] and Jim Belushi as Harvey, a party-goer on New Year's Eve.

[3] The film has numerous cameos, including singer Bo Diddley as a pawnbroker;[7] Curtis' sister Kelly as Penelope's friend Muffy; the Muppets puppeteers Frank Oz and Richard Hunt as, respectively, a police officer and Wilson, the Dukes' broker on the trading floor; and Aykroyd's former Saturday Night Live colleagues, Tom Davis and Al Franken, as train baggage handlers.

[2] Trading Places was developed with the intent to cast comedy duo Richard Pryor and Gene Wilder as Valentine and Louis Winthorpe III respectively.

[2] Curtis had performed recently in the slasher film Halloween II (1981) as a favor to director John Carpenter and producer Debra Hill; she was paid $1 million for that role, but received only $70,000 for Trading Places.

While filming the scene where Randolph and Mortimer collect Valentine from jail, Landis was positioned in a towing truck that pulled the Rolls-Royce carrying Ameche, Bellamy and Murphy.

Empty lockups in police administration buildings would normally be in use but because of the financial investment the production had made filming in the city, the mayor's office agreed to accommodate Landis' request; the studio paid for any expenses incurred.

[2] It was scheduled to take place during a weekday, but Aykroyd's and Murphy's presence on the floor distracted the active traders and over $6 billion of trading had to be halted; filming was rescheduled for a weekend.

[2] Ameche was opposed to using foul language and often apologized in advance to his crewmates for what he was scripted to say; he only performed one take of his final scene where he shouts "fuck him", referring to Randolph.

[37][39] Trading Places features songs including: "Do You Wanna Funk" by Sylvester and Patrick Cowley, "Jingle Bell Rock" by Brenda Lee, "The Loco-Motion" by Little Eva, and "Get a Job" by the Silhouettes.

The season featured expected hits such as the third installment in the Star Wars series, Return of the Jedi, Superman III, and the latest James Bond film Octopussy.

[42] Paramount Studios opted to release Trading Places at the start of summer, as those films expected to do well would benefit from being in theaters longer during this busy period.

[2] Reviewers compared it to the socially conscious comedies of the 1930s and 1940s, like My Man Godfrey (1936), Easy Living (1937), Christmas in July (1940), and Sullivan's Travels (1941) by directors like Preston Sturges, Frank Capra, and Gregory La Cava.

[43] Dave Kehr said that though the film pays homage to screwball comedies, it stripped the concept of all but the "crudest audience-gratification moments" and avoided exploration of the genre's moral conflicts.

[26] People said that the ending was perfectly presented, but Arnold considered it to be confusing and reliant on the audience's knowledge that the "heroes" were being heroic to compensate for a lack of clarity in their actions.

Bart believed its success triggered a negative trend that resulted in him receiving numerous film pitches—often a mix of the high-concept nature of Trading Places with a Flashdance-inspired breakdancing or gym setting.

This reflected the fact that average audiences were aging and now in their late teens to early 20s, and led to a shift in focus away from making films targeted mainly at children.

[65] His rapid rise to fame led to Murphy leaving Saturday Night Live the following year; he said he had grown to dislike the job and felt he was resented for his success.

[89] The film has also been compared to Twain's 1893 short story “The Million Pound Bank Note”, in which two brothers bet on the outcome of giving an impoverished person an unusable million-pound bank-note.

As part of their revenge against the Dukes, Winthorpe disguises his identity by donning blackface makeup, an act enabled by Valentine who has helped loosen up this strait-laced character.

In 2010, nearly 30 years after its release, the film was cited in the testimony of Commodity Futures Trading Commission chief Gary Gensler regarding new regulations on the financial markets.

[108] The testimony was part of the Dodd–Frank Wall Street Reform and Consumer Protection Act designed to prevent insider trading on commodities markets, which had previously not been illegal.

The site's consensus states: "Featuring deft interplay between Eddie Murphy and Dan Aykroyd, Trading Places is an immensely appealing social satire".

[129] In the years followings its release, some critics have praised the film while highlighting elements that they believe aged poorly, including racial language, the use of blackface, and the implied rape of Beeks by a gorilla.