Why Didn't They Stress Test Fannie Mae?

It takes some gaul for the Feds to pass judgement on the banks via the stress tests and their insistance on 4% tangible common equity when Fannie Mae has negative equity and is going hat in hand yet again for billions from you and I, while the banks are tripping over themselves to give the taxpayers their money back!

UPDATE: I shoulda thought of this..."Why Not Stress Test Pensions Too?"