Tooltip showing multiple values

So I have a line chart where each line is a company and the x-axis is over time. So you can see how companies are performing over time.  Based on the slicers the user may select between 1 to 30 companies.

The lines may bunch together or one line may swing up over time before going down again. It's these outliers the user is interested in.

So they would hover over a line that appears to be bucking the trend on that month and wanting to know which company it was. They are currently faced with a list of all companies currently in the chart and have to resort to matching up the color in the legend to the color of the line.

Hope that helps explain it better.