A new study obtained data from a firm that consolidates information on a number of superwealthy families (average net worth is $90 million) and tabulated their holdings and trades. You can find a summary here (subscription might be required). The good things the rich do is they don’t trade much, invest in vehicles open only to the wealthy (hedge funds and private equity), and take tax losses quicky. The rich have about six advisers or money managers each.
But they don’t do everything right. The wealthy have a tendency to chase fads with the money that isn’t invested for the long term. One example in the study is that they steadily increased holdings of mortgage-backed securities as the 2000s went along. The also own a lot of individual holdings, perhaps too many to keep track of and to keep costs under control. They also do a better job of rebalancing their portfolios regularly, but not as good of a job as they should.