broker is responsible to verify buyers and sellers account before buying or selling of stocks. SEBI is the regulator of stock market. Government does not directly involve in stock market but the policies issued by the government affect the market. Bank is responsible for fund transfer between the buyers and sellers account. Long means buying
short means Selling
Long unwinding means selling the stock that is already brought
short Unwinding means buying the stock that is already sold.Stock trading is gambling because of the amount of risk involved in it is greater than the reward.