Hmmm I don't see where it says the house keeps the losing bets, I think it charges a transaction fee, and pays out winners from a pool of losses from what I read, but good point in regard to a rally or sell off. I suppose in a rally or sell off an even payout might be an issue since its considered a long shot, but no bet is ever guaranteed to win, that's somewhat of a fallacy, because even in bullish climbs over a week or so you see dips for a day and so forth. I guess you could use a betting strategy to combat that also. Anyone know of any other prediction sites that are based more around a daily model? The only ones I have seen thus far seem to be based on these ridiculous random user created predictions that take months to resolve for very little payout etc. It would be cool to find something that was consistent, potentially profitable and not based on random chance. With markets at least you can analyze the potential outcome.