This paper is an empirical investigation of how traders react to public news in a market where there are lots of non-scheduled announcements, often arriving simultaneously. Using detailed trade information from the Nordic intra-day electricity market and GARCH models, this paper examines market participants’ reaction to news about sudden production and transmission failures on the electricity grid.
I divide the time of news announcement into three phases: the preannouncement period – the interval up to one hour before the hour of the public announcement of a message, the contemporaneous period – the same hour as the announcement of a message, and the post-announcement period – one hour after the hour of the announcement of a message.
I find effect of news on prices in the preannouncement period, indicating that private information exists and is being used for trading on the intra-day market.
