The problem is if the loans are sold at less than the book value (currently 41% on average for the sector) it means impairments, which consume capital.
GACS, ATLAS, the EC and the ECB: some light notes on the political economy of Italian NPLs
Jonathan Algar

[via @jeuasommenulle] I agree and disagree. Of course impairments on the sale could be a big problem but (i) some NPL have a capital charge so the equation is more impairments < capital charge and (ii) I’m not sure the sector is desperately trying to shore up capital. It’s trying to get rid of NPLs all right (I’m not sure why, by the way) but my opinion is that they are doing this under regulatory / supervisory pressure and they simply don’t want to destroy value by selling at 15% IRR investors when they book the NPL at 5% IRR. This is even more an accounting & economic problem than a regulatory or supervisory one. When you talk to the large banks it’s very clear. They just don’t want to sell and they don’t need CET1 but they feel forced to.