"don't need to diversify their holdings to have a luxurious life".<p>Good point, but they do need to diversify to fund billions on the kind of change-the-world projects that they've expressed interest in in the past:<p>a) Alternative energy.<p>b) Genome / disease research &#38; mapping.<p>c) etc.<p>The recent mega-philanthropy of gates / buffet / etc people @ the top realize that they have a chance to alter the course of human history in other ways that may require a ton of capitalization (vaccines, health, disease, geneome mapping, etc).