The static electric dipole polarizabilities of Nb-2-Nb-27 have been measured via a molecular beam deflection method. The clusters display per-atom polarizabilities that vary between 5.4+/-0.3 Angstrom(3) per atom (Nb-10) to 37.7+/-0.3 Angstrom(3) (Nb-13). The factor of similar to7 variation observed in the per-atom polarizabilities is the largest observed for any metal cluster system investigated thus far and implies large size-dependent variations in their electronic and/or geometric structures. (C) 2003 American Institute of Physics.