Citadel Securities' Rubner expects stock market to rebound after a brief fluctuation

Citadel Securities' Scott Rubner warned that recent U.S. stock market gains have driven the S&P 500 to rise 17% from its annual lows, but could face turmoil in the near term due to overvalued valuations, seasonal volatility in September and October and potential sell-offs from trend-tracking funds, but will eventually end the year with strong momentum.