Abstract: This disclosure provides a monoclonal population of highly sialylated multimeric binding molecules where the population includes IgM antibodies, IgM-like antibodies, or other IgM-derived binding molecules, where the population of binding molecules has a higher level of sialic acid content than is found in normal serum IgM. Also provided are methods of producing such monoclonal populations of highly sialylated multimeric binding molecules.