In a risk-neutral stochastic environment where bankruptcy is possible, it i
s well-established that coinsurance incentives may lead creditors to prefer
mergers over spin-offs, while shareholders may prefer spin-offs. This pape
r shows that there are two distinct reasons for this. One is due to the con
cavity of the debt payoff function in the face value of the debt, while the
other arises from imperfect covariation in ultimate firm values. For the l
atter reason, conventional measures of covariation are not sufficient to ev
aluate the impact on ex-ante debt value. Also considered are the effects of
mergers and spin-offs on investment decisions. (C) 2000 Elsevier Science B
.V. All rights reserved.