On behalf of the Scientific Committee of the de Finetti Risk Seminars, we
are glad to invite you to participate at the following Lecture
Erhan Bayraktar
University of Michigan
TITLE: MINI-FLASH CRASHES AND MODEL MISSPECIFICATION
ABSTRACT: Why do mini-flash crashes occur? Human errors, endogenous
feedback loops, the nature of modern liquidity provision, fundamental value
shocks, and market fragmentation are often implicated. We develop a model
which unifies aspects of the first three explanations. Our setup seems to
reproduce a number of features of recent mini-flash crashes. For example,
there are circumstances in which mini-flash crashes will not occur. When
they do, even just before their onset, market participants may not know
with certainty whether there will be a crash or spike or that such an event
is imminent at all. We appear to observe mini-flash crashes can happen in
both low and high trading volume regimes as well. To the best of our
knowledge, we also introduce a new paradigm for studying model
misspecification risks in an optimal trading context. Our approach is based
on making an explicit distinction between reality and our agents’ models
for reality. More precisely, each agent’s model for how a certain risky
asset’s price will evolve is wrong in two ways: His understanding of how
the price would move in his absence and how his actions affect prices are
both imperfect. In fact, aside from a single trivial case, none of our
agents ever know the correct price dynamics. We highlight how this
framework differs from other common methods for addressing trading model
misspecification risks including position limits, sensitivity analysis,
Bayesian model averaging, the worst-case framework, and interpolations
between the worst-case and classical setups.
LOCATION:
The seminar will be held on Wednesday, May 17, at 18.00, Aula di
rappresentanza, Dept. of Mathematics, Milano University, Via C. Saldini 50,
Milano.
A refreshment will be offered at 17.30.
Scientific Committee
Prof. Simone Cerreia-Voglio (Univ. Bocconi)
Prof. Marco Frittelli (Univ. degli Studi di Milano)
Prof. Fabio Maccheroni (Univ. Bocconi)
Prof. Massimo Marinacci (Univ. Bocconi)
Prof. Emanuela Rosazza Gianin (Univ. Milano-Bicocca)
Dott. Marco Maggis (Univ. degli Studi di Milano)