These periods may be as long as a month or as short as a minute, daily bars being the most popular. The public tend to place orders at the opening of the market, reacting to the previous day’s close. Open and close are only significant for periods with a definite break before the next opening, as with days or weeks. They should be ignored in analyzing intra-day charts or markets that are open 24 hours a day. Control For every transaction there must be a buyer and a seller – so the actual number of buyers and sellers is always equal.