Everybody blows it sooner or later. I think the main reason that I can now discern was the forward rolls, they wanted something special but perhaps they over-hedged at in inopportune moment too. Also, perhaps they sat on the new cash for too long cash after the SPO, but still had to pay the div on the new shares. Perhaps now that GK isn't CEO anymore the board 2nd guessed him and prevented him from controlling the portfolio and the SPO timing in a "too may cooks spoil the broth" scenario. We'll have to wait for the conference call Q&A to find out more clearly.
This is the biggest miss in AGNC history, but the results do show that they are willing to report bad news rather than attempt to cover it up.