The Big Short: Inside the Doomsday Machine is partly so well-known because it was made into a biographical comedy-drama film in 2015. The film version was directed by Adam McKay, a director known mostly for his comedic work. For example, McKay also directed the Anchorman movies, Talladega Nights, and Step Brothers, all starring Will Ferrell. McKay has a noted creative partnership with Ferrell, having also produced the comedy website "Funny or Die" with him. In fact, The Big Short was the first film he made without using Will Ferrell. This was his first foray into more dramatic territory, and paid off very well; McKay went on to win Best Adapted Screenplay for the film, and was nominated for Best Director, as well. The director's comedy background, however, did inform the tone of the film. Overall, the movie adaptation emphasizes the comic elements that already existed in Lewis' book; the quirky personalities of his characters, the irony inherent in Wall Street's refusal to recognize its imminent crisis, and the many lines of caustic dialogue. In this way, the movie provides an even more comedic and ironic spin on the material first written up by Lewis.
The movie version of The Big Short helped to make Lewis' text even more accessible to a popular audience. The film breaks up the story by focusing on three different characters, and their respective stories leading up to the housing crisis. Throughout, the film also breaks the fourth wall through celebrity cameos to explain financial concepts that the general public may not understand, but that are important for understanding the progression of the plot. It begins with Michael Burry, and profiles him as he discovers how unstable the housing market is, decides to bet against it, and ultimately makes a profit of over $2.69 billion. The second major character is the Deutsche Bank salesman Jared Vennett (renamed from Greg Lippmann), who understands Burry's analysis and attempts to sell the swaps to firms who will profit when the bonds fail. In the film, "Jared Vennett" then accidentally calls FrontPoint, which alerts the hedge fund manager, Mark Baum (renamed from Steve Eisman) to the situation, and convinces him to buy swaps because of his personal hatred for the banks. This version of events dramatizes the interaction between the characters who represent Greg Lippmann and Steve Eisman, making their interaction out to be a fateful accident in which Eisman's character is unintentionally alerted to the situation at hand. Then, the film goes on to feature Charlie Geller and Jamie Shipley (renamed from Charlie Ledley and Jamie Mai) who, also by accident, discover a prospectus by Greg Lippmann's character, which convinces them to invest in the swaps as well. Once again, the film makes out the interactions between these characters to be purely accidental and fortuitous, when they actually hinged on a purposeful partnership or exchange of information. However, in many moments where the film diverges from historical accuracy, there is a celebrity cameo to briefly explain the divergence. For example, when Charlie and Jamie discover a document revealing how bad the crisis is, the real Jamie Shipley comes on screen to admit, "OK, this part isn't totally accurate." But the film does then end on a similar note to the book: Greg Lippmann's character makes a huge amount of money, Steve Eisman's character becomes more gracious as a result of his experiences, Burry closes his fund after all the backlash he faces, and Ledley and Mai's characters go their separate ways. The film also concludes that CDOs are now being sold by banks under a new label: a "bespoke tranche opportunity."
Although the film changes some characters' names and exaggerates the importance of chance in bringing the characters together, it does tell the other aspects of the story very faithfully. This is the version of the story that much of the American public was exposed to, since the film was such a commercial success that, in some ways, it eclipsed the book. Charles Randolph, who adapted Michael Lewis' book for the screenplay, explained in an interview that Lewis' book lent itself easily to a movie adaption. In addition to viewing his characters through the lens of what they think and want, "He also has inherent cinematic characters." The movie brings out the quirks of these characters, whose personalities are so delicately described in the book. In doing so, it emphasizes one of the book's key themes: people's personalities were integral to how they reacted to life on Wall Street, and how they dealt with the shady practices going on behind the scenes. Randolph specifies that he started his screenplay adaptation by focusing on these characters, and bringing out their personalities through the film. As he says, "What The Big Short specifically has is a very unique, emotional character in Baum (Steve Carrell), who is the guy who becomes the very thing he procures. And I thought that was the best character response to the 2008 crisis, because the 2008 crisis is us realizing we are all guilty." The film adaptation of this book focuses specifically on the character of Steve Eisman, who becomes a kind of symbol for the collective public response to the housing crisis. Eisman represents "us realizing we are all guilty." In this way, the film elicits a more emotional response from viewers, encouraging them to recognize the collective guilt that everyone shares for this crisis. It builds on the story presented in Lewis' book, which also arrives at this conclusion but with less of an emotional punch, and speaks more personally to its viewers by explicitly bringing out shared guilt as a major theme of the story.
