“…(Panzar, 1994, p. 91)This difference in the type of network associated with postal services means that it is a controversial point whether any natural monopoly characteristics exist in it. The empirical economic literature on postal services tends to regard the stages before final delivery—in particular sorting and transportation—as functions where economies of scale are not significant (see for instance, Bradley & Colvin, 1995; Crew & Kleindorf, 1991, 1992; Owen & Willig, 1983; Panzar, 1991a,b, 1994; Rogerson & Takin, 1993; Sidak & Spulber, 1996). 3 The only part of postal services where economies of scale are said to be significant are collection and local delivery (Sidak & Spulber, 1996, pp.…”