The Federal Reserve has two statistical programs that I believe might address your question. The first is the Survey of Consumer Finances (SCF) and the second is the Flow of Funds (FoF). You should be able to find the data on the Fed's website.
Wealthy individuals have invested most of their money.
One of the biggest reasons for this is inflation. Most countries, especially those in the West, have a small, positive rate of inflation. Inflation is why a dollar when our grandparents were children was worth much more than a dollar is worth today.
If the "rich" simply stored their money in their ...