I would like to visualize the allocation of a financial portfolio by asset type and asset, where an asset or asset type could have a negative allocation. For example, we could have something like:
Asset type, Asset, Allocation
Equity, GOOG.OQ, 80%
Equity,HSBC.L, 40%
Fixed Income, US Treasury, -25%
What types of charts are best to visualize the allocation by both asset type and asset in a single chart?