In the heart of Chicago’s financial center, a seven-story building occupying much of a city block was once home to the world’s largest options exchange. Now, it’s collecting dust, Bloomberg News reported. The property, for decades home to the floor where options traders jostled and screamed orders at each other, has been on the market since 2019, but owner Cboe Global Markets Inc. can’t find a buyer. The Chicago Board of Trade building, once a key commodities hub, has fared even worse, with lenders handing the keys over to Apollo Global Management Inc. Over on the Magnificent Mile, the famed shopping strip that runs north of the Chicago River on Michigan Avenue, empty storefronts dot the streets, with vacancies at a record. CME Group Inc. Chief Executive Officer Terry Duffy said in an interview that he’s prepared to leave Chicago if the city and state take steps that are perceived as “ill-conceived.” Hollowed-out downtowns are a depressing characteristic of American cities right now, whether it’s Market Street in San Francisco or Wall Street in New York. But Chicago, the third-largest city in the U.S., faces its own challenges that threaten its status as one of the main global financial hubs. Not only has the Midwest’s commercial center been struggling with the slow return of workers — the region’s office attendance is about half of pre-pandemic levels, according to security firm Kastle Systems — but the departure of major companies including Citadel and Boeing Co. stands to leave a tough-to-fill void.