What is a series LLC and do I need one for multiple rental properties?

A series LLC is a single parent LLC that can create separate internal 'series,' each holding different assets with its own liability protection, without forming a brand-new LLC each time. Real estate investors like it because a lawsuit tied to one property theoretically cannot reach the others. But only some states authorize series LLCs, the liability firewall between series is largely untested in many courts, and states that do not recognize them may treat the whole thing as one entity. For most people with one or two properties, a standard LLC or separate LLCs is simpler and more predictable. Consult a local attorney before relying on a series structure, since state law drives everything here.