A hydrosilylation process is used to prepare a clustered functional polyorganosiloxane. The clustered functional polyorganosiloxane comprises a reaction product of a reaction of a) a polyorganosiloxane having an average, per molecule, of at least 2 aliphatically unsaturated organic groups; b) a polyorganohydrogensiloxane having an average of 4 to 15 silicon atoms per molecule; and c) a reactive species having, per molecule at least 1 aliphatically unsaturated organic group and 1 or more radical curable groups selected from an acrylate group and a methacrylate group; in the presence of d) a hydrosilylation catalyst, and e) an isomer reducing agent. The weight percent of silicon bonded hydrogen atoms in component b) divided by the weight percent of aliphatically unsaturated organic groups in component a) (the SiHb/Via ratio) ranges from 4/1 to 20/1. The resulting clustered functional polyorganosiloxane is useful in a curable silicone composition for electronics applications.