The UK stock market comprises large, multi-national corporations whose fortunes are not tied to the UK economy. As such, it is difficult to suggest that the political uncertainty could affect the long-term outlook for, say, AstraZeneca, or BP. There is a plausible scenario where an incoming administration seeks better relationships with its important trading partners to the benefit of all UK companies that trade internationally.
The UK market remains cheap by historical standards and the uncertainty surrounding the UK is largely priced in. The UK market has not fully recovered from the Brexit vote and valuations remain attractive. International investors have continued to avoid the region and the current political uncertainty may prolong this, but it does not change the fundamentals for UK businesses.
Equally, the UK stock market is well known for its bias to ‘value’ areas such as financials, energy, and mining. This means that the outlook for global economic growth, inflation and interest rates are likely to exert greater force on its performance than the ebb and flow of domestic politics. It remains too early to judge whether Johnson’s administration will be replaced by a government of fiscal discipline or higher spending. This will ultimately have an impact, but to make predictions would be perilous.