Credit risk at such maturities was arguably very low in those years, so that most if not all could be accounted for by devaluation risk. For yields at longerterm the gap was even higher – a regression approach suggests a spread of about 6–7% in the mid-1980s (Figure 3): but the influence of credit risk over the longer term would not be negligible.
It has also been unsurprising that the cash rate has traded slightly below the cash rate target since late-March 2020 (Graph 6). While ES balances will decline as the various monetary policy measures adopted during the pandemic unwind, as discussed, that process will take a number of years.