Let A be any n x n complex matrix. Let sigma (A) and W (A) denote respectively the spectrum and the numerical range of A. It is wellknown that if A is a multiple of a positive semidefinite matrix, then sigma(AB) subset of W (A)W(B) for all n x n complex matrices B. We show that the converse is also true. (C) 2013 Elsevier Inc. All rights reserved.