A method of displaying a symbol representative of changes in price during a time period in which a highest price occurred at a first time within the time period, a lowest price occurred at a second time within the time period, and a last price occurred at a third time within the time period, the method includes receiving a bid price and an ask price corresponding to a fourth time within the time period, wherein there is no new last price corresponding to the fourth time, determining whether the last price is lower than the bid price or higher than the ask price, in response to the determining that the last price is not lower than the bid price and not higher than the ask price, updating the last price to correspond to the fourth time, and generating, by a charting engine, the symbol by drawing, at a first luminosity level, a spatiotemporal relationship between the highest price, the lowest price, and the last price in accordance with a selected symbol rendering method, in response to the determining that the last price is lower than the bid price or higher than the ask price, generating an estimated last price from the bid price and the ask price, the estimated last price corresponding to the fourth time, and generating, by a charting engine, the symbol by drawing, at a second luminosity level, a spatiotemporal relationship between the highest price, the lowest price, and the estimated last price in accordance with a selected symbol rendering method, and displaying, by the charting engine, the generated symbol at a particular position.