Is Serum a listed company?

Excuse me, could you clarify something for me? I've been hearing a lot about Serum lately in the cryptocurrency space, and I'm wondering if it's a listed company or not. By listed, I mean is Serum traded on any major stock exchanges or do they have shares that are publicly available for purchase? It's just that I'm trying to understand the structure of the organization and where it fits within the broader financial landscape. Thank you for your help!