Hi Guys, I often notice that on yahoo finance and Interactive brokers, the line chart does not hit the listed high or low of the day. I thought line charts were supposed to include every print for the day? Is this not the case?
"...supposed to hit every print..." Oh god no. Your single line would be a mere blur through the millions of trades in a day, and market price info would be slowed to molasses as everyone, in essence, applied for by-tick timeXsales data. So, how to speed things along? 4 data points are collected for each defined cut of time -- the opening price, the high, the low, and the closing price -- ye ol' OHLC. Of those four, on which would you base a single line? The Open is the least relevant -- if the defined cut of time is a 1-day 'candle', then the open would put your line chart a full market day behind. The High is not relevant -- it's just a momentary thing...and EVERY other trade was less than that! The Low? What if the price was climbing all day? So we're left with the Close -- which handily enough, is also the *latest* information for that time period. ("Yayyyyy!")
You could have a line chart of the highs or of the lows. Most line charts are for the close of some period.