You might not accept Wikipedia as a source but anyways: https://en.wikipedia.org/wiki/Random_walk_hypothesis https://en.wikipedia.org/wiki/Random_walk_hypothesi

You might not accept Wikipedia as a source but anyways: https://en.wikipedia.org/wiki/Random_walk_hypothesis https://en.wikipedia.org/wiki/Random_walk_hypothesis > Professors Andrew W. Lo and Archie Craig MacKinlay, professors of Finance at the MIT Sloan School of Management and the University of Pennsylvania, respectively, have also presented evidence that they believe shows the random walk hypothesis to be wrong. Their book A Non-Random Walk Down Wall Street, presents a number of tests and studies that reportedly support the view that there are trends in the stock market and that the stock market is somewhat predictable. It's an open question/debate in academia whether the random walk hypothesis is true or false.