In Season 5 of Girls, Shoshanna was adrift after losing her job in Japan and returning to a life she didn't necessarily want back in New York. She seemed to find her footing again by the end of the season, and when Season 6 caught up with her it looked like Shoshanna was doing well with a new, impressive marketing job. In "Hostage Situation," she decided to kill too birds with one stone by reconnecting with old friends at a networking event for women entrepreneurs, where she could clear things up with them while also maybe landing a new opportunity. Her friends have had explosive success with a company called Jamba Jeans, but is Jamba Jeans from Girls a real company?
Owned by Shoshanna's old college friends Rachel and Ziva, Jamba Jeans allegedly "cracked open the market on athletic denim." They were doing so well that they were preparing to expand into T-shirts, and they had set up the W.E.M.U.N. (which stands up Women Entrepreneurs Meet Up Now) event for professional women to meet and work together. It all sounded great (Shoshanna was clearly impressed), but it was all fiction: there's no such thing as Jamba Jeans in the real world. If there was, they might be facing a copyright infringement lawsuit from Jamba Juice.
The idea of "athletic denim" is apparently not a new one, though, at least when it comes to jeans for muscular body types. But it wasn't totally clear in-episode just what Jamba Jeans meant by athletic denim. Jeans that fit especially muscular bodies? Workout gear that looked like denim (i.e., jeggings)? Workout gear made from denim (which definitely wouldn't be comfortable)? The world may never know.
Jamba Jeans wasn't a real company and doesn't even seem to have a real life counterpart; instead it existed to serve an important function in Shoshanna's story. Jamba Jeans represented everything she missed out on or gave up on, all of the decisions that led to the life she is currently living. Jamba Jeans served as Shoshanna's Sliding Doors; if she hadn't skipped out on the trip to Aruba where the company was conceived, then everything could be different. It could be perfect.
Girls is all about its four protagonists navigating their way through the world as they try to find some stability or purpose, even if that means missing out on opportunities or giving up on dreams. In "Hostage Situation," Jamba Jeans was more of a metaphor for that than anything else.