Helder Sebastião
University of Coimbra
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Publication
Featured researches published by Helder Sebastião.
European Journal of Finance | 2010
Helder Sebastião
This article examines the partial adjustment factors of Financial Times Stock Exchange (FTSE) 100 stock index and stock index futures. Using high frequency data from 15 January 1997 to 17 March 2000, it aims to assess the informational impact of the electronic trading systems implemented at the London Stock Exchange and London International Financial Futures Exchange (LIFFE). The results suggest that information runs mainly from the futures market to the spot market. We find that the introduction of stock exchange trading system, in October 1997, has increased the FTSE 100 indexs absolute efficiency; however, it reduced the informational feedback to the futures market. The implementation of LIFFE CONNECT at LIFFE, in May 1999, has reduced the absolute and relative efficiency of FTSE 100 futures. These findings seem to imply that during the period under scrutiny electronic trading increased the level of microstructural noise, probably due to the bid–ask bounce and order flow imbalances.
Scientific Annals of Economics and Business | 2018
Pedro Bação; António Portugal Duarte; Helder Sebastião; Srdjan Redzepagic
Abstract This paper investigates the information transmission between the most important cryptocurrencies - Bitcoin, Litecoin, Ripple, Ethereum and Bitcoin Cash. We use a VAR modelling approach, upon which the Geweke’s feedback measures and generalized impulse response functions are computed. This methodology allows us to fully characterize the direction, intensity and persistence of information flows between cryptocurrencies. At this data granularity, most of information transmission is contemporaneous. However, it seems that there are some lagged feedback effects, mainly from other cryptocurrencies to Bitcoin. The generalized impulse-response functions confirm that there is a strong contemporaneous correlation and that there is not much evidence of lagged effects. The exception appears to be related to the overreaction of Bitcoin returns to contemporaneous shocks.
International Transactions in Operational Research | 2017
Rui Pedro Brito; Helder Sebastião; Pedro Godinho
Journal of Asset Management | 2016
Rui Pedro Brito; Helder Sebastião; Pedro Godinho
Archive | 2008
Helder Sebastião
The Journal of Energy Markets | 2018
Márcio Ferreira; Helder Sebastião
Social Science Research Network | 2017
Márcio Ferreira; Helder Sebastião
Portuguese Economic Journal | 2017
Rui Pedro Brito; Helder Sebastião; Pedro Godinho
Notas Económicas | 2017
Helder Sebastião; António Portugal Duarte; Gabriel Guerreiro
Archive | 2017
Helder Sebastião; António Portugal Duarte; Gabriel Guerreiro