The chemical reactions and pathways resulting in the formation of a lysobisphosphatidic acid. A lysobisphosphatidic acid is a lysophosphatidic acid having the unusual property of a phosphodiester moiety linked to positions sn-1 and sn1' of glycerol; and two additional fatty acids esterified to the glycerol head group.
bis(monoacylglycerol) hydrogen phosphate biosynthetic process