The Security Performance graph has two options: by Price and by Value. When the Price option is checked, the lines have data points for all the periods selected. So far, so good.

When the Value option is checked, it seems that data points are only shown for periods when the security has Buy or Sell transactions. In the context of a 401k, a security may not have a Buy transaction if its value went down. It seems to me the graph should show a data point representing the current quantity times the period ending price. As it is, it does not show whether the value went up or down in periods when there was no activity on that security.

In the attached sample, the top two securities do have price updates, but do not have activity. They lines should continue to the end of the selected period, with relevant data points. But they stop in March, the last time there was a Buy activity for those two.