Bank treasuries generally have a broad range of funding channels available including deposits, covered bonds,
securitisation and unsecured funding. All of these various funding tools have their pros and cons from the issuer
perspective. Senior unsecured funding is probably the most flexible form as it does not restrict the composition
of the asset side. Covered bonds, on the other hand, require the issuers to maintain a cover pool of high quality assets backing the bonds. Moreover, regulatory rules and rating agencies often require that the mismatch
between the cover assets and outstanding covered bonds is limited and that the covered bond issuer holds a
certain amount of over-collateralisation (OC). In particular, the rating agencies often demand high OC level
going well beyond the legal requirements.
From an investor’s perspective, the secured character of covered bonds combined with their favourable regulatory treatment (low risk-weights, exemption from bail-in under BRRD, LCR-eligibility, etc.) make them an
attractive investment usually reflected in significantly lower spread levels than senior unsecured debt.
However, over the last few years the spread differentials between senior unsecured bank debt and covered
bonds have remained relatively low. Even the rise in overall yield levels since April 2015 has not triggered a
widening of the spread differentials. It seems that, in this low-yield environment, investors in search of yield are
inclined to accept the higher risk of unsecured paper in return for a few more basis points; this is particularly
true for shorter-dated senior unsecured paper and for bonds issued by strong institutions, where the downside
risks are often regarded as being smaller. In Figures 2 and 3 below, we compare individual bond pairs with
2017 maturity, allowing a maximum maturity mismatch of six months within each pair.