For defaulted bank loans, the resolution take time.
Banks need to model this time to resolution, or rather the probability of resolution, in function of the age since default, the client & loan type (large corporate, sme, mortgage, consumer, etc.), the economic situation, the legal & fiscal regime of the country, etc.
This is currently a new and active research field, and there's very few papers in the litterature, though the academic methods are readily available, such as Survival Analysis.
Please contact me if interested.