The main conclusions of the research: 1) If the mathematical expectation of return on speculation in financial markets is less than the current rate of return in the interbank credit market, a professional participant will close up his financial activities in financial markets and transfer his assets to the interbank market. 2) Financial markets provide the conditions for manipulative transactions when the mathematical expectation of return on speculative transactions goes below the current value of the interbank market return, with no funds flowing from the stock market to the interbank market. 3) The higher the dealer-estimated probability of success of his speculative strategy, the higher the risk he would be willing to assume (the higher quotation he would be willing to offer). 4) Information is not a mandatory component for the speculative dealer to carry out speculative trading. Certainly he may use it but he is basically indifferent to the information flow. 5) The modern exchange trading system accepted globally, including Islamic countries, violates a few fundamental principles of Sharia and cannot be used in Islamic countries.