Bad start to May is a sign of things to come for global markets

(Bloomberg) -- Sell in May and go away? The negative start to the month raises concern that the partial recovery in April is going to be about as good as it gets for risk assets.

For all the optimism stemming from the gradual easing of lockdown measures in some of the biggest economies, there are too many worries on the minds of traders to sustain the momentum from last month.

The fear of a second wave of infections, the collapse in corporate earnings and the shocks reverberating from the economic data are toxic enough.

Now throw in a fresh eruption of political sparring between the U.S. and China.