With $200 million under management and nascent operations in retailing and fashion, Assembled Brands is the vehicle for Mr. Pritzker’s sprawling ambitions. His new line of women’s clothing, Protagonist, is sold at Barneys. Next up is a foray into marketing and retailing at boutique hotels, another store in Los Angeles and the creation of new fashion brands. If successful, Mr. Pritzker will build on the business legacy of a family that boasts 11 living billionaires. Mr. Pritzker’s grandfather, Jay, who died in 1999, was the architect of the family empire. His father, John, is a billionaire hotelier. Another relative is Penny Pritzker, the commerce secretary. He helped found General Assembly, a real estate and education start-up. Mimi Chun quit Ideo and joined him. General Assembly was a hit, attracting $50 million in venture capital funding. Where exactly Mr. Pritzker’s $200 million came from remains unclear. His stake in General Assembly is included. Other family offices have contributed cash, but he declined to identify his limited partners. Members of Mr. Pritzker’s family, eager to see another one of their own succeed, have contributed significant sums.