I would like to identify big losers and backtest them according to the associated news events and to see if certain news events usually end up with a big recovery in stock price afterwards. I know of a website nyse.com that allows you to see historical news events and sorted according to various categories, but would like something even more specialized; alternatively, starting with a service that will easily identify the big losers (historical, for backtesting), and then to efficiently see the associated news event. Any input would be appreciated.