Matt Damon stars as a corporate whistleblower in the comic thriller The Informant! (Warner Bros. Pictures)

When you hear the term "whistleblower," you generally picture some courageous person of conscience who takes great personal and professional risks to expose a grave wrong. A classic example: Daniel Ellsberg, the subject of a moving new documentary at the Toronto International Film Festival, who was willing to face a lifetime in prison for leaking the Pentagon Papers.

Matt Damon is hilarious as corporate snitch Mark Whitacre, giving a performance so disarming that he's a shoe-in for an Oscar nomination.

Well, Mark Whitacre wasn't that kind of whistleblower. Whitacre, played to doofus perfection by Matt Damon in Steven Soderbergh's new film, The Informant!, wanted to have his exposé and profit by it, too. Not only that, he didn't seem to see the inherent contradiction in trying to climb the corporate ladder even as he was taking an axe to it.

In this funny, surprising film, Soderbergh and screenwriter Scott Z. Burns chop away at the whole whistleblower genre, from Silkwood to The Insider. What starts out as a mildly quirky investigative thriller – based on New York Times reporter Kurt Eichenwald's non-fiction book– just gets crazier and crazier. Before you know it, we've gone from following a lone man's takedown of a corrupt cartel to gasping in disbelief at his seemingly endless self-delusion.

The time is the early 1990s – when ugly patterned ties were apparently all the rage – and the place is Decatur, Ill., where biochemist Mark Whitacre has become a rookie VP at agri-behemoth Archer Daniels Midland. A nerdy kid en route to middle age, with a thickening waist and a wispy moustache to hide his baby face, Mark seems a mix of naiveté and smarts. Driving through Midwest cornfields, he rhapsodizes to his young son about all the wonderful things his company does. He's just the sort of idealist who, when he discovers his superiors are running a price-fixing scheme for one of ADM's products (the food additive lysine) might be prompted to turn informant for the FBI.

At the urging of his devoted wife, Ginger (Melanie Lynskey), Mark goes to the feds. In turn, his FBI handlers fix him up with a wire so he can trap his devious bosses. Mark takes to his spy role with reckless aplomb. In his over-active imagination, he's Agent 0014 – that is, twice as smart as 007. Up to that point, though, he's still endearingly innocent, a Jimmy Stewart without the humility. Then Mark, who has a compulsion to confide, begins revealing some startling things about himself, which throw the price-fixing scandal into the shadows and raise questions about his own trustworthiness.

From left, FBI agents Brian Shepard (Scott Bakula) and Bob Herndon (Joel McHale) have a clandestine meeting with Mark Whitacre (Damon) in The Informant! (Warner Bros. Pictures)

This is one movie where you really don't want to spoil the plot. Soderbergh hooks us from the moment Mark starts his loopy voice-over narrative, and then just reels us in. Like all good nerds, Mark's a repository of trivia, chattering to us about butterflies or the German word for pen. But he's also oddly unfocused for a guy putting his career on the line. While getting crucial instructions from the FBI, he's preoccupied with thoughts about patterned ties. And what kind of mole opens his briefcase in the middle of a meeting to fix his carefully concealed tape recorder?

Damon is hilarious as Mark, giving a performance so disarming that he's a shoe-in for an Oscar nomination. His co-stars spend much of their time looking gobsmacked – from a hangdog Scott Bakula as Mark's exasperated FBI contact, to a saucer-eyed Tony Hale (a.k.a. Buster of TV's Arrested Development) as his perpetually perplexed attorney. Only Lynskey's Ginger, a steadfast wife in the Tammy Wynette mode (but with a Betty Boop voice), remains unfazed by her hubby's off-the-rails behaviour.

Soderbergh – who seems to make a movie every other month – is at the top of his game here. He puts aside visual pizzazz and instead revels in the story's corporate-culture blandness. We're swept away by a wave of '90s tackiness, from the JCPenney wardrobes to Marvin Hamlisch's jaunty elevator-music score.

Under the laughs, though, The Informant! is more than just a highly entertaining tale of corporate malfeasance. Mark Whitacre, with his slippery grasp of both ethics and reality, could well represent the same skewed business mindset that helped bring about the current economic crisis.

The Informant! opens Sept. 18.

Martin Morrow writes about the arts for CBCNews.ca.