I don't know if it's accurate or just the tip of the iceberg. It may very well be the measurable amount that is being held by them but may not include other things that they may be doing with this wealth and the power that it can wield. There are an estimated $800 trillion in derivatives at this point in time. I don't think it would be much of a stretch to assume that these billionaires are mostly likely in control of large segments of the world's resources whether it be mineral, food, land, or heck, even information could be considered a resource really. Put into that kind of context with the $800 trillion guestimate in derivatives, then that means that although the fair value of their wealth may be only $5 trillion, they are most likely behind or responsible for a good segment of that $800 trillion in power. Derivatives can be used to do many things from locking in prices on a resource or stock or arbitrage on markets. I would say that the actual monetary power that they wield is probably somewhere between that $5 trillion and that $800 trillion.