As the US sharemarket teeters on the cusp of a bear market, analysts have barely started to adjust their earnings forecasts to reflect a severe economic shock that investment strategists fear could accelerate the meltdown on Wall Street.

The US President Donald Trump’s intensifying trade war has already sent the S&P 500 Index diving 15.3 per cent this year, extending its slide from a record in February to 19 per cent and placing the world’s most important equity gauge on the precipice of a bear market – which is a fall of at least 20 per cent from a recent peak.