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Enrico Scalas

Publications and source records attributed to Enrico Scalas.

66 records · Page 4Linked to original sources
arXiv2005

Basel II for Physicists: A Discussion Paper

On June 26th, 2004, Central bank governors and the heads of bank supervisory authorities in the Group of Ten (G10) countries issued a press release and endorsed the publication of "International Convergence of Capital Measurement and Capital Standards: a Revised Framework", the new capital adequacy framework commonly known as Basel II. According to Jean Claude Trichet, Chairman of the G10 group of central bank governors and heads of bank supervisory authorities and President of the European Central Bank: ``Basel II embraces a comprehensive approach to risk management and bank supervision. It will enhance banks' safety and soundness, strengthen the stability of the financial system as a whole, and improve the financial sector's ability to serve as a source for sustainable growth for the broader economy.'' The negotial process is likely to lead to the adoption of the new rules within 2007. In 1996, after the "Amendment to the capital accord to incorporate market risks", a new wave of physicists entered risk management offices of large banks, that had to develop internal models of market risk. Which will be the challenges and opportunities for physicists in the financial sector in the years to come? This paper is a first modest contribution for starting a debate within the Econophysics community.

cond-mat.other↗
arXiv2004

Uncoupled continuous-time random walks: Solution and limiting behavior of the master equation

A detailed study is presented for a large class of uncoupled continuous-time random walks (CTRWs). The master equation is solved for the Mittag-Leffler survival probability. The properly scaled diffusive limit of the master equation is taken and its relation with the fractional diffusion equation is discussed. Finally, some common objections found in the literature are thoroughly reviewed.

cond-mat.dis-nn↗
arXiv2003

Anomalous waiting times in high-frequency financial data

In high-frequency financial data not only returns, but also waiting times between consecutive trades are random variables. Therefore, it is possible to apply continuous-time random walks (CTRWs) as phenomenological models of the high-frequency price dynamics. An empirical analysis performed on the 30 DJIA stocks shows that the waiting-time survival probability for high-frequency data is non-exponential. This fact sets limits for agent-based models of financial markets.

cond-mat.stat-mech↗
arXiv2003

Fraudulent agents in an artificial financial market

The problem of insider trading and other illegal practices in financial markets is an important issue in the field of financial regulatory policies. Market control bodies, such as the US SEC or the Italian CONSOB regularly perform statistical analyses on security prices in order to unveil clues of fraudulent behaviour within the market. Fraudulent behaviour is connected to the more general problem of information asymmetries, which had already been addressed in the field of experimental economics. Recently, interesting conclusions were drawn thanks to a computer-simulated market where agents had different pieces of information about the future dividend cash flow of exchanged securities. Here, by means of an agent-based artificial market: the Genoa Artificial Stock Market (GASM), the more specific problem of fraudulent behaviour in a financial market is studied. A simplified model of fraudulent behaviour is implemented and the action of fraudulent agents on the statistical properties of simulated prices and the agent wealth distribution is investigated.

cond-mat.stat-mech↗
arXiv2002

Revisiting the derivation of the fractional diffusion equation

The fractional diffusion equation is derived from the master equation of continuous-time random walks (CTRWs) via a straightforward application of the Gnedenko-Kolmogorov limit theorem. The Cauchy problem for the fractional diffusion equation is solved in various important and general cases. The meaning of the proper diffusion limit for CTRWs is discussed.

cond-mat.dis-nn↗
arXiv2001

An empirical analysis of medium-term interest rates

In the present paper, an empirical study of LIBOR (London Interbank Offered Rate) data is presented. In particular, a data set of interest rates from 1997 to 1999, for two different currencies and various maturities, is analyzed. It turns out that the random behavior of the daily increments for the interest rates series is non-Gaussian and follows a leptokurtic distribution.

cond-mat↗
arXiv2000

The waiting-time distribution of LIFFE bond futures

We apply the Continuous Time Random Walk (CTRW) framework, introduced in finance by Scalas et al., to the analysis of the probability distribution of time intervals between two consecutive trades in the case of BTP futures prices traded at LIFFE in 1997. Results corroborate the validity of the CTRW approach for the description of the temporal evolution of financial time series.

cond-mat.dis-nn↗
arXiv2000

Fractional calculus and continuous-time finance

In this paper we present a rather general phenomenological theory of tick-by-tick dynamics in financial markets. Many well-known aspects, such as the Lévy scaling form, follow as particular cases of the theory. The theory fully takes into account the non-Markovian and non-local character of financial time series. Predictions on the long-time behaviour of the waiting-time probability density are presented. Finally, a general scaling form is given, based on the solution of the fractional diffusion equation.

cond-mat.dis-nn↗
arXiv1999

Correlations in the Bond-Future Market

We analyze the time series of overnight returns for the bund and btp futures exchanged at LIFFE (London). The overnight returns of both assets are mapped onto a one-dimensional symbolic-dynamics random walk: The `bond walk'. During the considered period (October 1991 - January 1994) the bund-future market opened earlier than the btp-future one. The crosscorrelations between the two bond walks, as well as estimates of the conditional probability, show that they are not independent; however each walk can be modeled by means of a trinomial probability distribution. Monte Carlo simulations confirm that it is necessary to take into account the bivariate dependence in order to properly reproduce the statistical properties of the real-world data. Various investment strategies have been devised to exploit the `prior' information obtained by the aforementioned analysis.

cond-mat.stat-mech↗
arXiv1999

Volatility in the Italian Stock Market: an Empirical Study

We study the volatility of the MIB30-stock-index high-frequency data from November 28, 1994 through September 15, 1995. Our aim is to empirically characterize the volatility random walk in the framework of continuous-time finance. To this end, we compute the index volatility by means of the log-return standard deviation. We choose an hourly time window in order to investigate intraday properties of volatility. A periodic component is found for the hourly time window, in agreement with previous observations. Fluctuations are studied by means of detrended fluctuation analysis, and we detect long-range correlations. Volatility values are log-stable distributed. We discuss the implications of these results for stochastic volatility modelling.

cond-mat.stat-mech↗