Texto interessante do que falamos aqui o dia inteiro.
Vamos ver se em inglês o pessoal entende :)
Bears Are Getting Desperate - Nasdaq.comIn a 1988 study conducted by Cutler, Poterba, and Summers entitled “What Moves Stock Prices,” they reviewed stock market price action after major economic or other type of news (including major political events) in order to develop a model through which one would be able to predict market moves RETROSPECTIVELY. Yes, you heard me right. They were not even at the stage yet of developing a prospective prediction model.
However, the study concluded that “[m]acroeconomic news . . . explains only about one fifth of the movements in stock market prices.” In fact, they even noted that “many of the largest market movements in recent years have occurred on days when there were no major news events.” They also concluded that “[t]here is surprisingly small effect [from] big news [of] political developments . . . and international events.” They also suggest that:
“The relatively small market responses to such news, along with evidence that large market moves often occur on days without any identifiable major news releases casts doubt on the view that stock price movements are fully explicable by news. . . “
In August 1998, the Atlanta Journal-Constitution published an article by Tom Walker, who conducted his own study of 42 years’ worth of “surprise” news events and the stock market’s corresponding reactions. His conclusion, which will be surprising to most, was that it was exceptionally difficult to identify a connection between market trading and dramatic surprise news. Based upon Walkers study and conclusions, even if you had the news beforehand, you would still not be able to determine the direction of the market only based upon such news.
In 2008, another study was conducted, in which they reviewed more than 90,000 news items relevant to hundreds of stocks over a two-year period. They concluded that large movements in the stocks were NOT linked to any news items:
“Most such jumps weren’t directly associated with any news at all, and most news items didn’t cause any jumps.”
