his paper investigates what motivates managers to conceal line-of-business (LOB)
information via segment aggregation. Aggregation is a central issue in financial reporting
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.