Banking on assumptions? How banks model deposit maturities
How do banks manage the behavioural maturity of non-maturing deposits (NMDs)? Using a rich and confidential dataset, we investigate how banks model deposit maturities based on internal assumptions. Although NMDs are contractually floating-rate liabilities with zero maturity, banks reallocate them across different maturity buckets using models that reflect past customer behaviour. Notably, only 20% of NMDs are treated as having zero maturity, while about 10% are assigned maturities beyond seven years. We assess whether these modelling assumptions align with banks’ deposit structures.