We propose global and disaggregated spillover indices that allow us to assess variance and covariance spillovers, locally in time and conditionally on time-t information. Key to our approach is the vector moving average representation of the half-vectorized 'squared' multivariate GARCH process...

The Mean-Variance (MV) portfolio by Markowitz (1952) and the Global Minimum Variance (GMV) portfolio represent standard rules for investment decisions and both rely on estimates of the inverse of the covariance matrix of stock returns. When working in a large-scale framework, where the...

Financial returns modelling assumes that price returns are normally distributed, which is problematic because it fails to capture “fat tails”, or extreme price swings, that are commonly observed in the financial markets. This has led to increased interest in alternative distribution models...

A low frequency factor model regression uses returns computed at a lower frequency than data available. An example is using monthly rather than daily returns to estimate the Capital Asset Pricing Model (CAPM). I show that when using overlapping observations to estimate low frequency factor model...

We compare several models that forecast ex-ante Bitcoin one-day Value-at-Risk (VaR), starting from the simplest ones like Parametric Normal and Historical Simulation and arriving at Historical Filtered Bootstrap and Extreme Value Theory Historical Filtered Bootstrap. We also consider Gaussian...

We make use of the extant testing methodology of Barndorff-Nielsen and Shephard (2006) and Aït-Sahalia and Jacod (2009a,b,c) to examine the importance of jumps, and in particular large and small jumps, using high frequency price returns on 25 stocks in the DOW 30 and S&P futures index. In...

The topic of volatility measurement and estimation is central to financial and more generally time series econometrics. In this paper, we begin by surveying models of volatility, both discrete and continuous, and then we summarize some selected empirical findings from the literature. In...

Simple, multi-step estimators are developed for the popular GARCH(1,1) model, where these estimators are either available entirely in closed form or dependent upon a preliminary estimate from, for example, quasi-maximum likelihood. Identification sources to asymmetry in the model's innovations,...

This study investigates the lead-lag relationships and volatility dynamics among four major cryptocurrencies - Bitcoin, Ethereum, Solana, and Polygon - during the turbulent year of 2022. We address three primary research questions: (1) To what extent do lead-lag relationships exist among major...

This paper focuses on the estimation and testing of multiple breaks that occur at unknown dates in multivariate long memory time series regression models, allowing for fractional cointegration. A likelihood-ratio based approach for estimating the breaks in the parameters and in the covariance of...