The search for yield is on - and not just in bond markets. With ultra-loose central bank monetary policy squashing high-quality bond yields to negative levels in real terms, dividend-paying stocks are becoming an increasingly favoured source of income. That could be an enduring trend.

The 30-year bull market for bonds has driven yields below equity dividend yields - a rare occurrence. Ten-year US Treasuries yield just 1.8% while the estimated forward dividend yield on the S&P 500 is 2.3%, according to FactSet. In Europe the gap is even bigger, with German Bunds yielding 1.5% while the Europe Stoxx 600 index yields 4.2%.