While it is allegedly said to be tied to the return rate of the cash investment, the truth is they can manipulate their figures to claim that they are right, knowing full well that their is no one or no entity that will investigate if they are massaging the figures to amounts that they can advertise for a seemingly larger jackpot. We all know enough basic human nature to know or suspect that this is what their doing. It's interesting how the exchange rate changed so dramatically about the same time that the states started running both games and having to compete for the right to claim the higher advertised jackpot. I have e-mailed the IA lottery/Powerball public liaison and told them that jacking the advertised jackpot in such a way makes them look a little shady and gives purchase to those who think the Lotteries are fixed anyway. They basically responded with a "Who thinks that? Nobody thinks that it is illegitimate. Prove it." The interesting thing to notice is with the advertised Jackpot size being the deciding factor, and with their limited jackpot growth cap rules, is that if someone hits, let's say a $390 million pot, which is the next record cap limit "record" Jackpot, the actual cash value of the Jackpot would be a hell of a lot smaller than the previous Jackpot record mark. And if I could find historical data on past drawings like MM provides, I'm relatively guessing that the second to the previous Jackpot record amount would actually be significantly less actual cash value than the "new record" Jackpot would provide allowing them to crow all over the media about the new record Jackpot size while not even being worth as much as the second record mark. E-mailed them pointing this out, and surprise, they haven't replied yet. The first time they have not replied over the years.