Random and regular stock price change depending on a time span

The purpose for the research is to identify the correlation between random (accidental) stock price changes and its well-known tendency to grow depending on a time span. In contrast to the works of other scholars on the issue of the random nature of stock prices the presentation of the issue is new in the current research. The research method consisted of identifying the criterion stock price change separation into random and regular components and further comparing the proportions between random and regular stock price change on the example of 10 stocks of the largest world-known companies from representing different economic sectors traded on New York stock exchange for several time spans: one day, week, month, quarter, half-year and one year. The main research results suggest that with the increase in time span the share of the regular origin of the stock price increases, but only up to a certain significant limit. The increase in the time period of analyzing the stock price changes (fluctuations) does not prove that the random character of stock price change has an unlimited downward trend...