Billionaire Ken Griffin's Citadel created a bubble for interns at a resort in Kohler, Wisconsin, renting out the entire place. The firm had already been operating a bubble at Palm Beach's Four Seasons hotel since early April for its Citadel Securities trading floor, and dozens of interns went to Florida for a month as well. Out of the firm's 235-person intern class, roughly 100 spent a month in Wisconsin, while 35 went to Florida.