"Value" is relative...therefore, trading exists. If you believe the PPS is undervalued (as many of us do), why would you sit on a bid, if you can gain by hitting the ask? Only one answer: Greed. Trouble with that Greed is two-fold. 1). If enough traders convince MM, the value is in the Bid, MM will undercut Ask or NSS the OS. 2). Just like a pps can crash, a pps can moon (and I'd hate to be bid-sitting) during the moon shot. Happy Trading.