The question is, when the banks "lost 75% of their loans". To my knowledge, this happened much later, when the banks that initially where in danger already got rid of the most toxic loans. Those loans either went to the EU "Rescue Umbrella" or where sold (with discounts).
When those sold loans later where haircut, than the lost value of 75% was on papers, but the value that those holders really lost very likely much smaller (if any), because they bought the loans with huge discounts.
When those sold loans later where haircut, than the lost value of 75% was on papers, but the value that those holders really lost very likely much smaller (if any), because they bought the loans with huge discounts.