The deregulation of the telecommunications industry and its convergenc
e with the broadcasting and computer industries have led to a variety
of alliances within the redefined sector: The paper uses recent develo
pments in the economics of a corporate structure to provide some tools
for an analysis of these moves. It focuses on the firm's choice of in
ternal organization, boundaries and alliances. After a brief recap of
mergers and alliances in the three industries, the paper reviews the t
hree possible motivations for such moves : efficiency, acquisition of
market power, and objectives of entrenched managers. It then uses a fo
rmal model to provide a definition for the usually loose concept of co
re competency and to determine a firm's legal boundaries and sphere of
influence as a function of its headquarters' ability to oversee activ
ities. Last, it derives some implications of the analysis for the orga
nization of R&D.