The trial will take 2 or 3 weeks and the trier of fact, here a Jury, will have to decide whether or not Fannie Mae and Freddie Mac breached the implied covenant or contract that all shareholders have with the corporations they invest their hard earned capital with. That contract is simple, I invest my capital and as the owner of the corporation I am to share in the future profitability and not have the corporation give away all their future profitablity to a third party.
Then the Jurors will have to determine "with reasonable certainty", the amount of the losses from the breach of the Implied contract with shareholders and the corporations will have to pay the shareholders with assets from their balance sheet (e.g., cash).
But guess whose likely going to appeal the Jury verdict and determination of economic damages?
Although courts are typically reluctant to mess with Jury verdicts, they could possibly in the future do so if a compelling procedural appeal is made...