A kinetic model of hyperbranched polymerization is presented where an AB(2) monomer reacts with up to 10% of a B-3 one (A and B are functional groups) to yield a hyperbranched polymer. The model consists of two compact rate equations for entire distributions of two kinds of molecules that are formed in the system. Changes in reactivity of B groups in the form of the so-called first shell substitution effect are taken into account. Molecular parameters, namely the number and weight averages of polymerization degree as well as the average degree of branching of hyperbranched molecules, are extracted out from the rate equations and plotted against conversion.