I made the decision to go see “The Informant!” for a particularly odd reason. I had seen the trailer on television and was intrigued by its promise of comedic corporate hijinks. Several critics praised Matt Damon’s work in the film after it screened at the Venice Film Festival. The movie’s director, Steven Soderbergh, is one of the industry’s most eclectic directors, mixing light star vehicles (the “Ocean’s” franchise) with a curious range of passion projects (the two-part “Che,” his “Solaris” remake, “Traffic”), but almost never failing to entertain. But what really made me fork over $6.50 for that matinee showing? That silly little exclamation point in the title. It winked mischievously out at me from the marquee, impishly thumbing its nose at expectation, promising a satisfaction with my film-going experience beyond that of those other, non-punctuated movies. How could I resist?

The exclamation point, luckily, was not deceiving me, although it wasn’t telling the whole truth either. “The Informant!” is, for sure, a sly and humorous take on white-collar crime. But as it bounces merrily along, it makes room for a few subtle jabs at the two-sided nature of corporate America. This is not an intensely self-important corporate thriller like “The Insider,” nor is it a purely comical romp like those in the “Ocean’s” movies.

The film is based on the true story of Mark Whitacre, the vice president of a large agri-business company called ADM. In the early 1990’s, ADM was one of the largest manufacturers of cornstarch in the world. So you know all those products you eat containing high fructose corn syrup? These guys are responsible for them, and controlling what Americans consume every day for breakfast, lunch and dinner provides a pretty little profit. At the beginning of “The Informant!” ADM’s success appears to have attracted the envy of one of its foreign competitors: Mark Whitacre reports to his boss a suspicion that a new chemical compound the company is developing is being sabotaged by a mole.

An FBI agent is called in to verify the claim and is startled when, after some fairly standard investigation, Whitacre suddenly divulges ADM’s role in a global price-fixing scheme. His conscience has been clouded by his company’s shady dealings, Whitacre says, and he’s taking the opportunity to clear his name before he can get pinned as a fall guy. Whitacre agrees to become an informant for the FBI, gathering evidence by making tapes of price-fixing meetings. For almost three years, Whitacre and the government work hand in hand to bring down the company, but just when they seem to have closed the deal, Whitacre throws a wrench in the works.

“The Informant!” uses the tried-and-true device of the bungling spy to entertaining effect; whether it’s “Get Smart” (the original show), “Austin Powers” or any of the other infinitely many James Bond spoofs out there, there’s something inherently funny about the secret agent who isn’t quite as smart as he thinks. But thanks to the enigma that is Mark Whitacre, the film takes on another layer as an intriguing character study. The audience can immediately tell that there is something “off” about Mark Whitacre; he tends to depart into rambling internal monologues that seem to have nothing to do with the action on screen, expounding on polar bears, butterflies, immoral Japanese businessmen and, of course, corn.

At first, this mindless jabbering causes us to view Whitacre in the same light: mindless. But there is a common thread behind Whitacre’s sermons. They all speak of deception and appearances that defy the truth; one does not expect a professional businessman in a suit to buy used girls’ panties out of a vending machine or jumbo shrimp to be fed corn. Things are not as they seem to be, and Mark Whitacre is not exactly a dimwit. Matt Damon gained about 30 pounds to play the role, giving Whitacre the physical appearance of the spoiled, pudgy child that he essentially is. Damon, who has played both straight comedic roles (having worked with Soderbergh in the “Ocean’s” movies) and much more complex psychological pieces (the severely underappreciated “The Talented Mr. Ripley” and the Jason Bourne franchise), was the perfect actor to play the mysterious goofball and is the key to the film’s success. Given what we learn about Mark Whitacre, the performance will surely be even more impressive after a second viewing.

Soderbergh has fun with the spoof half of the film, using a score heavy on brass to evoke the ridiculous spy-thriller music of old TV shows and films. Whitacre, as an executive at a prominent international company, trots the globe like any good secret agent must, but the film amusingly introduces cities like Decatur, Illinois with the same fanfare as Zurich and Mexico City. However, if you go into “The Informant!” expecting nothing but the merriment connoted by that puckish exclamation point, you’re missing something a little more relevant. After serving almost nine years in jail, Mark Whitacre is once again the COO of a biotechnology company. And, as the news constantly reminds us, corporate crime has remained alive and well after even the fall of ADM. Is the joke really on us?