The richest man in Illinois invited pop star Katy Perry to play the 25th anniversary party of his Chicago hedge fund, Citadel.

Perry allegedly charges $500,000 per set and played at this year’s Super Bowl, but money is no object for Griffin. The hedge fund billionaire recently finalized a divorce, and is still worth $7.1 billion, according to DNA Info.

Ken Griffin Has Katy Perry At Citadel Birthday Party

Massive Chicago celebration marks 25 years of growth at Citadel

Left Shark performed alongside Perry at a lavish bash which took place just a few weeks after Griffin’s birthday. Perry was obviously not chosen for her politics, with the staunch Clinton supporter singing at a bash organized by the generally conservative Citadel CEO.

The high-profile event was attended by 1,500 guests commemorating the 25th anniversary of Citadel, and was held at Cinespace Chicago in the Lawndale district. Other parties are being planned for New York and London.

Griffin reportedly made a speech at the Chicago event, thanking those involved in the transformation of Citadel from a small firm which managed just $500 million in assets to a hedge fund behemoth with over $25 billion on its books. He gave special thanks to his mother, who was present in the crowd.

Further parties planned in New York and London

The Citadel CEO then introduced Perry, who sang for over an hour before a cameo from Left Shark, the backup dancer who found fame during Perry’s Super Bowl halftime performance. Food at the event was provided by RPM and Frontera Grill, and as the festivities ended around midnight food trucks handed out take-home tacos to any guests that were still feeling peckish.

The Citadel party in New York will be headlines by Maroon 5, while the headliner for the London event has not been confirmed. Celebrating the success of Citadel comes at a good time for Griffin, who only recently reached a settlement in an acrimonious divorce battle that had dragged on since July 2014.

A divorce trial was set to begin on October 5 this year, but Griffin and estranged wife Anne Dias Griffin reached a settlement a couple of days before. Griffin apparently has plenty left in the bank even after the settlement. It looks like he is enjoying the single life.

Below is Citadel’s letter to investors on the occasion of the hedge fund’s 25 anniversary:

Dear Investor,

As we mark our 25th anniversary, I want to take a moment to express my gratitude for your trust and support over the years.

I’ve often thought of successful entrepreneurs as individuals who have just the right expertise — at just the right moment — to solve the emerging problems of their time. When I started Citadel 25 years ago, my expertise in software engineering and mathematics created significant competitive advantages in a world where the power of computational finance was appreciated by few.

But the opportunity that was born of that fortunate positioning would never have grown into the success of today without crucial early support. Frank Meyer, co-founder of Glenwood Partners, empowered the formation of Citadel with his willingness to take a chance on an unproven twenty-year-old portfolio manager. With the tailwind of strong early returns, and the enthusiastic support of our investors, Citadel took off.

In our firm’s earliest days, our understanding of the power of great software engineering and quantitative analytics helped Citadel stand out. But history is littered with companies started by entrepreneurs who failed to sustain such early bursts of success. In fact, the average lifespan for a hedge fund is just a few years. What, then, has driven our longevity and our success? The answer is simple: Our sustainable competitive advantage doesn’t just come from our technical prowess; it comes from assembling teams of extraordinary individuals who have the creativity, resourcefulness, ambition and tenacity to take on the world.

The early days of Citadel had a constant rhythm: research, problem-solve, program, trade, interview. Repeat. In our first decade, I interviewed about five thousand people in pursuit of the talent that would create our future. As our success grew, we became known across the four corners of finance not just for our outstanding returns, but also for our outstanding people.

Today, I’m proud that Citadel is seen as a beacon for the best and brightest. It is incredible to come to work every day surrounded by individuals whose insights and efforts place us at the forefront of finance. As I reflect upon the exceptional team that is Citadel today, I believe our greatest moments lie not in our past, but in our future.

Over the past twenty-five years, I have enjoyed a remarkably challenging and rewarding career — a career defined by the extraordinary people for whom and with whom I have worked. Thank you for your continued support and for your trust in my team and in me.

With all my best,

Ken