I like the descriptions and explanations of government debt in this thread, so I’m not going to bother to try to add to those.
Instead, I’ll address the other aspect of government debt: its necessity to investors.
Investment Characteristics of Government Debt
Government debt is viewed as risk-free of default. Countries like the US, UK, France, Germany etc. are seen as being absolutely 100% reliable when it comes to being able to pay the debt back and 100% on the nose when it comes to the timing of the payments too.
From an investment point of view, this is frequently essential.
The concept of Liability Matching
Investment is not normally about earning as much as you can. Instead, it’s about earning as much as you can subject to meeting your liabilities as they fall due.
Suppose that you have a liability that results in you having to pay $4 per year every year for the next 20 years. Suppose further that there is a government bond that pays $4 per year every year for the next 20 years. This means that you can purchase the government bond and your liability is taken care of. No risks, no problems, your ability to pay your liability stream is assured. This idea is called matching
That sounds like a simplistic example but it’s not too far removed from many situations, particularly when we’re looking at things like pension funds. Here’s a slightly more complicated example:
Matching in the context of a pension fund
Suppose a pension fund has $10m. It needs to pay out $400k per year until its members die. What does it invest its money in? Let’s say that the options are 20 year 5% government bonds and equities.
The equities may look more attractive. They certainly have a higher expected return than government bonds. But their trouble is one of uncertainty. Suppose all $10m is invested in equities and the economy experiences recession. Dividends drop below the 3% mark and all of a sudden you don’t have the liquidity to pay your pensions. This forces you to sell some of those equities… at the bottom of the market. Not good. Even worse, there are often statutory regulations requiring you to value your assets at market level. This means that a typical violent equity market swing may leave you technically insolvent even though your asset base is unchanged!
All in all, 100% investment in equities in such a case is too risky. But if we invest $8m in the 5% bonds, we know that we’ve got our pension payments covered no matter what. The average life expectancy post retirement is less than 20 years, so the 20 year lifetime should be sufficient and we can always reinvest later if necessary.
We now have $2m left over to invest as we wish - typically for maximum return.
I’ll stop there before really launching into financial economics, since this subject can be 100x more complicated. Rest assured however that this is how you need to think if you are investing in the context of a pension fund or similar.
Conclusion
Institutions such as pension funds, life companies and insurance companies (to some extent) view government bonds as absolutely crucial to their management. But who are the recipients of life policies and pensions? Us! So the stability of our long term financial futures are all dependent on the existence of a sizable and liquid government bond market.
I’m not sure quite how big that market needs to be. But bear in mind that typically less than 50% of a pension fund is invested in equities and an even smaller percentage of a life company’s funds and note that 70% of the stock market is owned by these institutions! That implies that the government bond market needs to be very large indeed.
So next time you worry about government debt, remember this: without it we’d all be screwed.
pan