Using firm-level data, we estimate the effects of the major wave of 1991 br
eakups of Czechoslovak state-owned enterprises on the subsequent performanc
e of the "master enterprises" and spun-off divisions. We estimate the perfo
rmance effects of spinoffs by comparing the performance of enterprises that
remained intact throughout the 1990-1992 period to the performance of the
master enterprises that experienced spinoffs and the newly spun-off subsidi
aries. Our estimates suggest that the breakups had a significant immediate
effect on the productive efficiency and on the profitability of industrial
firms in 1991, and that the effect became much less significant in 1992. Th
e effect is a negative function of the size of the spinoff, being positive
for small to slightly above average-sized spinoffs and negative for very la
rge ones. We cannot reject the hypothesis that the estimated effect was ide
ntical for the spun-off subsidiaries and the master enterprises that experi
enced the spinoffs. Our 1991 estimates suggest that the large firms created
under the centrally planned system suffered from inefficiencies that were
alleviated by the breakups. The 1992 estimates are consistent with increase
d competition and the appropriation of profits by managers.