Risk aversion and the dynamics of optimal liquidation strategies in illiquid markets

We consider the infinite-horizon optimal portfolio liquidation problem for a von Neumann–Morgenstern investor in the liquidity model of Almgren (Appl. Math. Finance 10:1–18, 2003). Using a stochastic control approach, we characterize the value function and the optimal strategy as classical solutions of nonlinear parabolic partial differential equations. We furthermore analyze the sensitivities of the value function and the optimal strategy with respect to the various model parameters. In particular, we find that the optimal strategy is aggressive or passive in-the-money, respectively, if and only if the utility function displays increasing or decreasing risk aversion. Surprisingly, only few further monotonicity relations exist with respect to the other parameters. We point out in particular that the speed by which the remaining asset position is sold can be decreasing in the size of the position but increasing in the liquidity price impact.      

Thinking about ... leadership. Warts and all

Does using Tyco's funds to purchase a $6,000 shower curtain and a $15,000 dog-shaped umbrella stand make Dennis Kozlowski a bad leader? Is Martha Stewart's career any less instructive because she may have sold some shares on the basis of a tip-off? Is leadership synonymous with moral leadership? Before 1970, the answer from most leadership theorists would certainly have been no. Look at Hitler, Stalin, Pol Pot, Mao Tsetung--great leaders all, but hardly good men. In fact, capricious, murderous, high-handed, corrupt, and evil leaders are effective and commonplace. Machiavelli celebrated them; the U.S. constitution built in safeguards against them. Everywhere, power goes hand in hand with corruption--everywhere, that is, except in the literature of business leadership. To read Tom Peters, Jay Conger, John Kotter, and most of their colleagues, leaders are, as Warren Bennis puts it, individuals who create shared meaning, have a distinctive voice, have the capacity to adapt, and have integrity. According to today's business literature, to be a leader is, by definition, to be benevolent. But leadership is not a moral concept, and it is high time we acknowledge that fact. We have as much to learn from those we would regard as bad examples as we do from the far fewer good examples we're presented with these days. Leaders are like the rest of us: trustworthy and deceitful, cowardly and brave, greedy and generous. To assume that all good leaders are good people is to be willfully blind to the reality of the human condition, and it severely limits our ability to become better leaders. Worse, it may cause senior executives to think that, because they are leaders, they are never deceitful, cowardly, or greedy. That way lies disaster.     

Term structure modelling of defaultable bonds

In this paper we present a model of the development of the term structure of defaultable interest rates that is based on a multiple-defaults model. Instead of modelling a cash payoff in default we assume that defaulted debt is restructured and continues to be traded.The term structure of defaultable bond prices is represented in terms of defaultable forward rates similar to the Heath-Jarrow-Morton (HJM) (Heath et al., 1992) approach, and conditions are given under which the dynamics of these rates are arbitrage-free. These conditions are a drift restriction that is closely related to the HJM drift restriction for risk-free bonds, and the restriction that the defaultable short rate must always be not below the risk-free short rate. In its most general version the model is set in a marked point process framework, to allow for jumps in the defaultable rates at times of default.Financial Assistance by Deutsche Forschungsgemeinschaft, Sonderforschungsbereich 303, at the University of Bonn and the DAAD is gratefully acknowledged.I thank Pierre Mella-Barral, David Lando and David Webb for helpful conversations, and the participants of the FMG Conference on Defaultable Bonds (March 1997) in London and the QMF 97 conference in Cairns for helpful comments. All errors are of course my own.     

When should a leader apologize and when not?

When corporate leaders or the organizations they represent mess up, they face the difficult decision of whether or not to apologize publicly. A public apology is a risky move. It's highly political, and every word matters. Refusal to apologize can be smart, or it can be suicidal. Readiness to apologize can be seen as a sign of character or one of weakness. A successful apology can turn enmity into personal and organizational triumph--while an apology that's too little, too late, or too transparently tactical can open the floodgates to individual and institutional ruin. Since the stakes are so high, Kellerman says, leaders should not extend public apologies often or lightly. One or more of the following conditions should apply: The apology is likely to serve an important purpose. The offense is of serious consequence. It's appropriate that the leader assume responsibility for the offense. The leader is the only one who can get the job done. The cost of saying something is likely lower than the cost of staying silent. The author draws her conclusions from hard data and abundant anecdotal evidence, examining notoriously bad apologizers as well as exceptionally good ones. While selectivity is key, good apologies usually do work. What constitutes a good apology? Acknowledgment of the mistake or wrongdoing, acceptance of responsibility, expression of regret, and assurance that the offense will not be repeated.