The story about the Dukes' cornering of the orange juice market was probably inspired by the "Silver Thursday" market crash of 27 March 1980, during which the Hunt brothers of Texas tried to corner the silver market and subsequently failed to meet a $100 million margin call.
The main titles are accompanied by the overture to "The Marriage of Figaro" by Wolfgang Amadeus Mozart, and in an early scene, as Louis is leaving his office he whistles the beginning of the aria "Se vuol ballare" from the opera. In that aria, Figaro declares his plan to turn the tables on his master - just as Louis and Billy Ray will eventually outwit the Duke brothers.
A scene in the movie not included in the final cut but seen frequently when the movie is shown on television (presumably to fill a longer time slot with commercials) occurs after Clarence Beeks talks to the Dukes via telephone and Billy Ray eavesdrops on their scheme. In the original cut, Beeks goes from the phone booth to the Amtrak train platform, holding the briefcase with the crop report. In the added scene, we see Beeks procure the reports from a secured vault where he pays off a security guard and opens a safe-deposit box.
Don Ameche's strong religious convictions made him uncomfortable with swearing. This proved a problem for the scene at the end of the movie where he had to shout out "Fuck him!" to a group of Wall Street executives. When he did act out the scene, it had to be done in one take because Ameche refused to do a second one.
Randolph and Mortimer Duke later appear in Eddie Murphy's movie Coming to America (1988), where, in a cameo appearance, the two are homeless on the street and Prince Akeem gives them a large amount of money to get them back off the streets.
Winthorpe's watch - a "Rouchefoucauld" is named after French writer François de La Rochefoucauld. Winthorpe names six cities with the intention that the watch tells six different time zones, which is not the case. Monte Carlo, Paris, Rome and Gstaad all share the same time zone, so the watch tells only three.
The exterior shots of Louis Winthorpe's house are of a real house on a very affluent street in Philadelphia. The wreath on the door was replaced when the producers wanted something bigger and better. They borrowed a hand-made wreath from a house across the street.
The film was conceived as a vehicle for Gene Wilder and Richard Pryor. But when Pryor dropped out and Eddie Murphy came on board, he made a motion to get Wilder replaced because he didn't want people to think he was just trying to be another Pryor.
The premise is similar to that of Hoi Polloi (1935), The Three Stooges film. Two rich guys are arguing about what matters most: breeding or upbringing. One bets the other they can take any bum off the street and make him a gentleman.
Frank Oz has a cameo as a police officer who is checking in Winthorpes property when he gets arrested. In the Blues Brothers, also directed by John Landis, he plays an officer who is giving Jake Blues his property back to him.
In the opening montage of Philadelphia there is a shot of the Rocky statue erected in Rocky III (1982) that was released the previous year and was still sitting at the top of the "Rocky" steps in front of the Philadelphia Museum of Art. The statue now resides at the base of the museum steps.
The home used in the film is not the Rosenbach Museum and Library, but is a private home two doors west. Both houses, however, were built at the same time and originally had an identical floor plan. During the filming of the movie, DeLancey Place was closed for a few days. Denholm Elliott was the only actor in the film to visit the Rosenbach. The staff of the museum were all given Pennsylvania State Film Commission tee shirts.
Several scenes were kept in the movie, even though they were considered either goofs or errors. The scene where Mortimer is trying to catch the money clip and having trouble wasn't supposed to happen that way, but both kept going with it and not breaking character, so it was kept in. Another, where Jamie Lee Curtis is doing her lines on the train and is questioned about her accent and outfit not matching, wasn't supposed to be shown either. Curtis couldn't do the correct Austrian accent.
Randolph Duke has a picture of Ronald Reagan on his side of the Dukes' shared desk, while Mortimer has a picture of Richard Nixon. Bryan Clark who portrayed Stock Exchange Official #2 has often played former President Ronald Reagan.
When Winthorpe and Valentine arrive at the World Trade Center, Winthorpe tells Valentine "In this building, it's either kill or be killed". This line was removed from some TV broadcasts after 2001, out of respect for the victims of the September 11th attacks.
Eddie Murphy later admitted that while on the floor of the stock exchange in the final scene, he only followed the script, he had no idea what was going on as he found stock trading incredibly confusing.
The barbershop quartet song sung by Todd and his pals at the tennis club is sung to the tune of "Aura Lee" an American Civil War song written by W. W. Fosdick (words) and George R. Poulton (music). Elvis Presley's "Love Me Tender" is a derivative of it as well. Another version of Aura Lee is done in Revenge of the Nerds (1984) It's the song the Pi's sing to offer themselves as dates to the the Tri-Lambs (Hello Lambdas we're the Pi's/And we're here to say/We think you are special guys/Lambdas all the way...)
In 2010, as part of the Wall Street Transparency and Accountability Act, which was to regulate financial markets, a rule was included which barred anyone from using secret inside information to corner markets, similar to what the Duke brothers tried to do in the movie. Since the movie inspired this rule, it has since become known as the Eddie Murphy Rule.
When Valentine chases Winthorpe out of the Christmas party he grabs a man in a Santa Claus suit. This man is Mike Strug, a television reporter who still works for a network affiliate in the city of Philadelphia.