Opinion 

Harnessing the predictive power of the yield curve

John Bilton

John Bilton

An interesting feature of investor behaviour is how we interpret themes from outside of the asset classes where we normally focus.

Bond investors seeking to explain yield changes might look to equity earnings, and stock investors might try to reconcile equity valuations with central bank policy forecasts.

Markets are, of course, inextricably linked.

But just as we would rigorously scrutinise asset markets with which we’re most familiar, we should be careful in blithely applying accepted “rules of thumb” from other asset classes.

As yield curves around the world flattened over the last few years, warnings of flat curves foretelling economic problems increased proportionally.

Over the long run, there is good evidence of the predictive power of the yield curve, especially for the US. 

Indeed, we’d go as far as to say that when the US yield curve is inverted, it provides a meaningful de-risking signal.

However, an inverted yield curve and a flattening yield curve are two very different things; moreover, non-US yield curves have significant local nuance – particularly the UK gilt curve.

Since the early 1960s, an inversion in the US yield curve – measured as US 10-year yields less cash or Fed funds rates – preceded all seven recessions.

There were two false positives: one in 1966, as fiscal tightening a couple of years earlier pushed the US into a mid-cycle slowdown, and another in 1998 around the time of the Asian financial crisis.

With this kind of hit rate, it is little wonder that investors watch yield curves closely – especially when they are flattening. 

History suggests that while an inverted US yield curve is a signal for caution, a flattening yield curve is not.

In the nine phases of US curve flattening since the early 1960s, the S&P 500 returned, on average, over 30 per cent from when the curve began flattening up to the point that it first inverted.

But from the point of the curve first inverting to the point of maximum inversion, S&P 500 returns were on average -2.5 per cent.

Indeed, a curve flattening is a natural by-product of a rate hiking cycle and is common in the later stages of the business cycle. So while we do closely watch the yield curve, we think it is rather too early to call time on the expansion.

With base rates in the UK just 0.5 per cent, but the US seven hikes – and counting – into their hiking cycle, this front effect is no longer a feature.

Nevertheless, there are still local market nuances to consider in calibrating the predictive power of the UK curve.

The first is that around a quarter of the outstanding stock of Gilts is held by the Bank of England, and this is unlikely to change until well into a UK hiking cycle.