Molecules that interfere with the binding of a tumor necrosis factor receptor with its ligand, such as a soluble receptor or an anti-receptor antibody, have proven usefulness in both basic research and as therapeutics. The present invention provides antibodies that bind two tumor necrosis factor receptor family members: the transmembrane activator and calcium modulator and cyclophilin ligand-interactor (TACI) receptor, and the B-cell maturation (BCMA) receptor.