In the given context, it appears to be coverage for losses incurred during the listing a home offered for sale with the real estate broker/agent. I think it's actually part of that "Dubbelboendekostnadsförsäkring" and "basförsäkring" describes the basic plan, with an option for additional coverage as "Tilläggsförsäkring." See the reference link for a description of the coverage in Swedish from a real estate broker. The coverage is underwritten by Lloyd's -- I'll try to find an English term and advise if I do.