The S&P 500 could jump a further 20% as the US recovers from a 'rolling recession', market veteran Ed Yardeni says

• US stocks could rally a further 20% as the economy recovers from a "rolling recession," Ed Yardeni said. 
• "For those who are waiting for a recession, I think we've had it all along," he said. 
• Yardeni also grounded his optimism on bullish earnings forecasts and a broadening of the equity market rally. 

US stocks stand to rally a further 20% over the next 18 months as the US economy improves, according to market veteran Ed Yardeni.