The literature offers a wealth of evidence both supporting and contradicting efficient market theory
Many less precise discussions of the efficient market theory
equate the theory with the property that speculative price changes exhibit a random walk around the fair expected return.
He wrote a number of influential books on a wide range of topics, including Capital Ideas on the efficient market theory
(1991), Against the Gods: the Remarkable Story of Risk (1996), and Wedding of the Waters: The Erie Canal and the Making of a Great Nation (2005).
While perhaps not striking at the heart of the efficient market theory
, it surely will result in discussion about how to modify the theory.
According to the popular Efficient Market Theory
, stock price variations are random and, as such, are not predictable.