Some Chicago bars say they are enjoying one of their most profitable times of the year—and owners and managers say it is all due to March Madness.

The first two days of the annual, nationwide college basketball tournament are “crucial” to their business’ yearly revenues, multiple bar owners told WBEZ in phone interviews on Wednesday.

“It turns a Thursday into a very, very, very good Saturday and it turns a Friday into the best Saturday you’ve ever had,” said Joel Sorinsky, owner of Theory, a sports bar in downtown Chicago.

He said patrons will stay and drink at his Hubbard Street watering hole from “11 a.m. to 11 at night” during the first Thursday and Friday of the tournament, when some 32 games will be played.

“Towards a given Thursday and Friday alone, we probably do 50 percent higher these next two days than we do any other Thursday or Friday of the year,” he said.

Sorinsky and other downtown bars representatives also said they will also make profits from selling out private space to companies. Stephen Strebing, a manager at Public House, said the bar has sold space to multiple companies, often for thousands of dollars.

He said these sales “enhance” the bar’s annual revenues.

And coupled with St. Patrick’s Day festivities, many other downtown taverns said the nearly three week long basketball tournament turns March into a vital month for their business’ health.

The tournament tips off on Thursday and runs until the final game on April 8.