This paper investigates what motivates managers to conceal line-of-business (LOB)
information via segment aggregation. Aggregation is a central issue in financial re-
porting and to some extent is determined by mandated standards. Where a mandated
standard exists, however, considerable managerial discretion is often allowed in how the
standard is applied. We argue that, with respect to the number of segments firms report,
this was the case to a great extent under SFAS No. 14 and is so to a lesser extent under
the current SFAS No. 131. 1 We therefore exploit the change to SFAS No. 131 segment
reporting to examine two possible motives for discretionary nondisclosure (i.e., aggregation)
of segments under SFAS No. 14, namely, proprietary costs and agency costs.
Our investigation of segment reporting contributes to the empirical literature on discre-
tionary disclosure choices. Empirical tests of voluntary disclosure often aim to test the
predictions of theoretical models. The traditional motive offered by the literature to explain
nondisclosure in general (e.g., Verrecchia 1983) and aggregation of segments in particular
(e.g., Hayes and Lundholm 1996) is that disclosure reveals proprietary information. 2 This
motive is also the one most often put forward by managers. For instance, Ettredge et al.
(2002) report that 86 percent of the industrial firms that commented on the Exposure Draft
for SFAS No. 131 opposed the new standard on the grounds that ‘‘it would put them at
competitive disadvantage.’’ It is therefore not surprising that prior empirical studies focus
primarily on examining the proprietary costs of segment disclosure (e.g., Harris 1998;
Piotroski 2003; Botosan and Stanford 2005). These papers generally find evidence consis-
tent with disclosure being constrained by proprietary costs.
We argue that much of the prior evidence consistent with the proprietary cost hypothesis
is also consistent with an alternative ‘‘agency cost’’ hypothesis that posits disclosures are
withheld as a result of conflicts of interest between managers and shareholders. Neverthe-
less, prior segment reporting papers do not attempt to directly test whether managerial self-
interest plays a role in segment aggregation decisions. Even in the broader empirical dis-
closure literature, scant evidence exists on the agency cost motive for withholding
disclosure. 3
Segment reporting is potentially fertile ground for examining the impact of agency
conflicts on disclosure decisions. Prior research provides evidence that multi-segment firms
trade at a discount relative to stand-alone firms (the ‘‘diversification discount’’) and that
internal capital markets in firms with diversified LOB transfer funds across segments in a
suboptimal manner (e.g., Lang and Stulz 1994; Berger and Ofek 1995; Lamont 1997; Shin
and Stulz 1998). Moreover, Berger and Hann (2003) find that firms that started reporting
multiple segments (as opposed to one segment) when SFAS No. 131 came into effect
experienced an increase in their diversification discount in the year of the disclosure change.