Alternative investments

I’d like database to track and report our alternative investments. Similar to what can be done with a spreadsheet or a access template that uses quotes pulled from the web data for stock prices. The difference is some of the investment are private companies and convertible debt ( i.e. unit of account changes when converted from debt to stock). Also, need to track values at point in time. We currently have all of this in excel with rows representing assets and columns representing transactions that “rollforward” from month to month.