abstract = "Financial contagion refers to a scenario in which
small shocks, which initially affect only a few
financial institutions or a particular region of the
economy, spread to the rest of the financial sector and
other countries whose economies were previously
healthy. This resembles the 'transmission' of a medical
disease. Financial contagion happens both at domestic
level and international level. At domestic level,
usually the failure of a domestic bank or financial
intermediary triggers transmission by defaulting on
inter-bank liabilities, selling assets in a fire sale,
and undermining confidence in similar banks. An example
of this phenomenon is the failure of Lehman Brothers
and the subsequent turmoil in the US financial markets.
International financial contagion happens in both
advanced economies and developing economies, and is the
transmission of financial crises across financial
markets. Within the current globalise financial system,
with large volumes of cash flow and cross-regional
operations of large banks and hedge funds, financial
contagion usually happens simultaneously among both
domestic institutions and across countries. There is no
conclusive definition of financial contagion, most
research papers study contagion by analysing the change
in the variance-covariance matrix during the period of
market turmoil. King and Wadhwani (1990) first test the
correlations between the US, UK and Japan, during the
US stock market crash of 1987. Boyer (1997) finds
significant increases in correlation during financial
crises, and reinforces a definition of financial
contagion as a correlation changing during the crash
period. Forbes and Rigobon (2002) give a definition of
financial contagion. In their work, the term
interdependence is used as the alternative to
contagion. They claim that for the period they study,
there is no contagion but only interdependence.
Interdependence leads to common price movements during
periods both of stability and turmoil. In the past two
decades, many studies (e.g. Kaminsky et at., 1998;
Kaminsky 1999) have developed early warning systems
focused on the origins of financial crises rather than
on financial contagion. Further authors (e.g. Forbes
and Rigobon, 2002; Caporale et al, 2005), on the other
hand, have focused on studying contagion or
interdependence. In this thesis, an overall mechanism
is proposed that simulates characteristics of
propagating crisis through contagion. Within that
scope, a new co-evolutionary market model is developed,
where some of the technical traders change their
behaviour during crisis to transform into herd traders
making their decisions based on market sentiment rather
than underlying strategies or factors. The thesis
focuses on the transformation of market interdependence
into contagion and on the contagion effects. The author
first build a multi-national platform to allow
different type of players to trade implementing their
own rules and considering information from the domestic
and a foreign market. Traders strategies and the
performance of the simulated domestic market are
trained using historical prices on both markets, and
optimizing artificial market's parameters through
immune - particle swarm optimization techniques
(I-PSO). The author also introduces a mechanism
contributing to the transformation of technical into
herd traders. A generalized auto-regressive conditional
heteroscedasticity - copula (GARCH-copula) is further
applied to calculate the tail dependence between the
affected market and the origin of the crisis, and that
parameter is used in the fitness function for selecting
the best solutions within the evolving population of
possible model parameters, and therefore in the
optimization criteria for contagion simulation. The
overall model is also applied in predictive mode, where
the author optimize in the pre-crisis period using data
from the domestic market and the crisis-origin foreign
market, and predict in the crisis period using data
from the foreign market and predicting the affected
domestic market.",