We use LMSR for pricing and cost calculation, thus there is no need to wait for someone to buy. The LMSR model offers a spot price. Predyx is still considered a play money market due to the micro bets nature, not sure if that will be a taxable event, but our legal team is actively looking into any kinda regulations that we need to follow.

More about LMSR (credit @ek) : http://blog.oddhead.com/2006/10/30/implementing-hansons-market-maker/

Our twitter post on LMSR: