Chris Weston, head of research at Pepperstone, said US President Donald Trump's tariffs represented the toughest of all possible scenarios. Harsh tariffs do not seem likely to be reduced anytime soon, he said. Investors are likely to be more cautious about stocks, and tariffs have exacerbated currency and cross-asset volatility. However, Weston added that the bottom line is that this will not trigger a full-blown risk aversion or a 10% drop in the S & P 500.