I state this because a stock swap would cost JPM no cash up front, and because although their short-term stock shareprice would take a loss in making a swap to finish acquiring the former WAMU, that loss would be negligible to the relative value they could try and spin to their current shareholders in doing so.
JPM - despite serious book-cooking over the last couple of years is an asset rich (relatively), but cash-poor company. Cash payout Vs a stock-based transfer would look better on their books. So it would be a way of further hiding what it is they gained relatively from the below-cost aquisition of WAMU to the defecit that JPM itself was in prior to their being gifted WAMU's assets.
Since (IMO) there is an incentive to their hiding the fact that they were, themselves, insolvent - a stock based swap would help them cover their butts.
While I agree (in general) that the relative value of the company that used to be WAMU was (perhaps) $50-100 / share at current valuation, the settlement value (assuming such) will be quite a bit less than that potential value.