Ken Griffin is seeking a divorce from his wife of 11 years, Anne Dias Griffin. (Patrick T. Fallon/Bloomberg News)

When one of the world’s richest financiers “unilaterally” files for divorce from his high-profile wife, who has a hedge fund of her own, it’s bound to get interesting. And expensive.

Ken Griffin — a Chicago hedge fund executive worth $5.5 billion, according to Forbes — is splitting from his French-born wife of a decade, Anne Dias Griffin. Crain’s Chicago broke the news Wednesday, reporting that “the divorce could be contentious.”

The Griffins have been separated for more than a year. In the Cook County Court divorce petition that was made public Thursday, Ken Griffin said “irreconcilable differences” have caused an “irretrievable” breakdown of their marriage, the Chicago Tribune reported.

The divorce petition also says that he is seeking joint custody of their children, ages 6, 3 and 2.

Dias Griffin, 43, is no minor figure: She’s a well-known French-born financier who runs a $100 million hedge fund, Aragon Global Management.

Her 45-year-old husband runs Citadel Investments and is one of the richest men on the planet, ranking 275th on the Forbes list of the world’s wealthiest and just outside of the American Top 100.

His estranged wife has secured the legal services of Robert Stephan Cohen, a New York divorce lawyer who, according to the New York Post, often represents the wives of hedge fund managers and billionaires. In a statement Wednesday, Cohen said:

Ken Griffin unilaterally filed a divorce petition today with no notice to either me or my client, knowing full well that she had just left for summer vacation with their three young children and would therefore be unable to respond. Anne’s highest priority remains her family, especially the wellbeing of her children. She is hopeful that this personal matter can be resolved privately and in the best interests of her children. We have no further comment at this time.”

The Griffins married in 2003, holding their wedding reception at the the Palace of Versailles, outside Paris.

On paper, they were an impressive match. She graduated from the Georgetown School of Foreign Service, and then Harvard Business School. He was a Harvard undergrad. She runs a $100 million hedge fund. He runs a mega-billion-dollar hedge fund, which he started in his dorm room in 1987.

Since marrying, the Griffins have used their influence and wealth to support culture, politics and education. They donated $19 million to the Modern Wing of the Art Institute of Chicago through the Ken and Anne Griffin Foundation, and he made a $2.5 million campaign contribution to Illinois Republican gubernatorial candidate Bruce Rauner — “the biggest single Illinois political donation … in the modern-day era,” according to the Chicago Sun-Times.

According to NBC Chicago, Griffin is “an active political funder for a range of politicians from former Chicago Mayor Richard M. Daley to current boss Rahm Emanuel on the Democratic side to Republicans including New Jersey Gov. Chris Christie and presidential also-ran Mitt Romney.”

Dias Griffin recently launched Reboot Illinois, which NBC Chicago described as a “conservative-leaning political site.”

Ken Griffin also made a $150 million donation to Harvard College earlier this year — the largest in the school’s history.

In a statement, his attorney, Karen Krehbiel, said: “This is a personal matter and the family asks for privacy as it works through this process and focus on the well-being of their children.”