I was wondering about people's opinion about investing in a future where the US has negative population growth. This day is likely not far into the future, considering that birth rates are well below replacement and immigration is now restricted. I predict that neither of those facts will change into the near future.
Now, I do not think population decline is all bad for a country. There are lots of examples of countries that have had declining populations for many years now, yet remain prosperous. A declining population likely ease housing prices, cause wealth transfer from parents to children to increase wealth (fewer beneficiaries to split up the estate), and reduce environmental stress. At the same time, this decline means fewer consumers of goods, difficulty servicing public debt, and increasing difficulty caring for the elderly.
But how will this trend affect investing in stocks? Individual companies can still grow, but there is a good chance that the overall economy contracts (but probably not GDP per person). And obviously, US companies are connected to the world, many parts of which will continue to develop and grow.
Note: I consider the decline in immigration to be mostly a permanent situation in that Americans generally favor restrictive immigration and perhaps equally important, Latin America (where most immigrants come from) is rapidly developing and increasing in wealth. This trend will reduce the immigration pressure dramatically as the reasons for leaving are generally economic.