I think I saw that for every 2 shares they are paying out something like $8, then reverse splitting them down to 1 share (1:2). All of the outstanding shares will combine to own 25% of the firm, and they will issue 75% to T Mobile.
To me, if you take a company then essentially buyback half of it's shares almost $2 below the market (by way of a special dividend and reverse split) and then sell 3/4 of it to some other firm, then the shareholder loses 75% stake for 2 bucks less than the market price for half of their stake.
I think the market is pricing for a higher bid. I'm not sure what's going on here.
At the end Metro PCS shareholders will get 4 bucks and also have 26% of combined company i.e. MetroPCS+T mobile ( 26% value of future company at current rate = current market cap - special dividend 4 $ per share). So it's favourable for current shareholders but not sure how this combined company can compete with stronger competitors, that's why price is staying low!