How Much Investment Income Do We Need to Compensate for Inflation?

 

This chart compares the fitted investment income curve from my previous post about the "boiling point" with the monthly loss of value of our portfolio (including our house) due to inflation. I just took the monthly percentage change in Australia's consumer price index and multiplied by the value of our portfolio that month. The gap between the blue and orange curves is a naive estimate of how much can be spent each month in retirement mode.

Currently, projected investment income is only just enough to cover the loss from inflation. Smoothing inflation over twelve months tells a similar story:

Here I divide the CPI by its value twelve months earlier, take the twelfth root and subtract one before multiplying by the value of the portfolio. This shows that inflation is coming down a little but is still high. We really need to boost our rate of return relative to inflation in order to retire and maintain the real value of the portfolio. It is hard to think about retiring until in inflation is more under control.

Investment income accounts for superannuation taxes, but assumes that the only tax on investments outside superannuation is exactly equal to the franking credits paid.* In retirement, the superannuation tax would go away, but there would be capital gains and other taxes on investments outside superannuation. So, probably it is in the ballpark.

* This is because the series is computed as the change in net worth minus saving and inheritances. Saving is computed after tax including superannuation contribution taxes and income tax.