Unless Matt suddenly comes up with something wholly unrelated to securities fraud ie he knows of cocaine deals happening tomorrow or Jihadi's, then the Government's deal encompasses ALL securities fraud he knows about. If he were to even hint that he has more to give in return for furthur reduction in sentence, that original deal will go up in smoke.
matt holds no hole cards here. The government has by far the upper hand.
The point Jarta is making is you don't get to renegotiate the deal once a plea agreement has been reached with the prosecutor.
You don't get a second bite at the apple by claiming that your attorney stiffed you in the first deal that was struck and you don't get to say time out I have more goods to offer up and I want a better deal.
That said the subject is moot. It appears that the prosecutor requested that change in attorney, the defendent didn't protest and everything was filed under seal.