Most fund managers learn modern portfolio theory from colleges. The theories are faulted. However, some gained Nobel prizes using the faulted theories - a bad reflection on today's silly Nobel Prize committee not to mention the silly award to President Obama for doing nothing but reckless spending. They do not invest with real money. I and many others have proved them wrong many times.
Walking randomly in the stock market postulates the price of a stock is already built-in, so there is no need to evaluate stocks. It is also known as the efficient-market hypothesis. Explain to me why as a group my stocks with high scores always beat my stocks with low scores for years. If you cannot find a functional scoring system, it does not mean all the scoring systems do not work. For the same reason, there is no need to take college courses to evaluate stocks if the prices are built-in.
When the professor writes equations on the board, he is dreaming and his fantasy world will never resemble reality. However, you need to waste time to ‘learn’ in order to get good grades. Without good grades from a prestigious college, you cannot get a good job.
The so-called modern portfolio theory is most likely based on wrong or insufficient testing parameters / assumptions. Unfortunately they're still supported by the Ivory Towers. All the students taking these courses should ask for refunds from these universities. Most likely these professors are still driving an old Toyota and have never made good money in the stock market besides in 'teaching', selling 'books' and/or running hedge funds to cheat you out of your money.
I’m still waiting for the counter arguments to prove me wrong. Professors, please drop me a line to defend yourself. So far, there is none.