Unfortunately we won't know until around 2017.
There's a rapidly-emerging segment these days, and it's called entry-level luxury. Take it for what it is, but automakers are quickly cashing in. Examples include the Audi A3 and Mercedes-Benz CLA. Both are attracting many first-time customers to both respective automakers. So it makes complete sense for Cadillac to offer an entry-level competitor of its own. Only right now it doesn't have one, but that'll change within just a few short years.
Cadillac president Johan de Nysschen has already acknowledged the automaker is working on such a model. He also admitted it'll be rear-wheel drive and be based on a shortened version of the same platform that underpins the ATS. Sweet. And now rendering artist Theophilus Chin has come up with a pair of images showing what this new Caddie could look like. Yes, it does look like a more compact ATS sedan but is that necessarily a bad thing? Not at all. Unfortunately we'll have to wait until 2017 at least in order to see the production version.