Can any of the telerik controls make a true "heatmap" .. i.e. one that's based strictly on data and not laid over an actual geographical map.
In that case, the data set is something along the lines of:
Sector (Light Blue)
Symbol - label for each box
Market Cap - Size of each box
Today's return - Color of each box, scaled from -3 for red to +3 for green.
Syncfusion has this: http://www3.syncfusion.com/products/user-interface-edition/wpf/chart/heat-map