Worsening US trade tensions with China break S&P 500's momentum

Returning from vacation is a drag — in life, in stocks. True to form, September started with the worst S&P 500 retreat since June.
 
Anyone hoping last month’s momentum would persist was disappointed. After hitting a record on Aug. 29, the index has fallen on five of six days, with the twin tech pillars of semiconductors and the FAANGs leading the way.
 
Historically, volatility is lower than average during the summer months before September flips the switch, according to Vinay Viswanathan, a derivatives strategist for Macro Risk Advisors. While realised volatility is typically suppressed from April through August,