A chart that describes price movement in an easy-to-understand format. Each dayÂ’s price movement is represented by a vertical line that shows how high and how low the security traded. The closing price is indicated by a short horizontal line, called a tick mark, which runs through the vertical line. Sometimes the trading volume is depicted below the price information as a horizontal line that rises or falls in accordance with the volume. At the very bottom of the chart, open interest, which is the amount of futures or options contracts that are available for trading in the market, are drawn to scale using vertical lines. The higher the line, the higher the open interest.