The FTSE 100 is trading at pre-2000 lows as fears about the outcome of the Brexit negotiations mingle with worries on the trade dispute between the US and China.
Fears about the nature and impact of the UK’s imminent exit from the European Union have dogged the FTSE 100 companies exposed to the British domestic economy but since these businesses make up a minority of the index the main market enjoyed a rally last year.
But fears about the impact of a trade dispute on the Chinese economy have meant companies mostly exposed to the global economy are also falling.
The FTSE 100 index was 7,320 on December 7 a year ago and is currently 6,798.
At the turn of the millennium, on the first day of trading of January 2000, the market was trading at 6,930 - though these are absolute numbers and exclude dividends received by investors during that time.
Laith Khalaf, senior analyst at Hargreaves Lansdown said: "The FTSE 100 now sits below where it stood at the turn of the century, when the dot com boom was in full swing and the pressing concern of the day was the millennium bug.
"It’s tempting to conclude the stock market has gone sideways, and in one somewhat peculiar sense it has, but even those who invested at the peak of the dot com bubble have still made gains since 1999.
"That’s because the headline FTSE 100 index ignores dividends paid by UK companies, which are a huge source of the total return payable to investors. The index also fails to take account of medium and smaller companies, which have performed significantly better than the big blue chips since 2000.
"However on the other side of the ledger, the index doesn’t reflect the costs of investing either, in the form of dealing commissions, stamp duty, and fund management charges.
"These make the index return unachievable in practice, unless you have an active manager who outperforms. Some have done so, though the average UK fund is very slightly short of the index over this period, but only to the tune of 0.04 per cent a year."
Richard Marwood, UK equity income fund manager at Royal London Asset Management said his preference was to own a broad range of UK equities, as the uncertainties that pervade in the economy and stock market were too broad to justify taking very strong sector positions on.
Brian Dennehy, who runs Dennehy Weller, an advice firm in Kent, said the sources of political instability, of which Trump and Brexit were the outcomes, was public unease at technological change, demographic change which slows economic growth, and high levels of personal debt.
He said those trends were "not going away", and so neither political worries.
Mr Dennehy said if volatility continues "ETFs will get a good kicking, as many investors, large and small, experienced and novice, realise ETFs are a very aggressive choice, and that they might just need to do something more intelligent than chase low charges."