S&P 500 Index: 30% gains since April came after the market hours – JP Morgan

In a recent research note, the JP Morgan analysts explain why all of the 30% gains in the S&P 500 index since April came after the regular market hours.

Key quotes (via CNBC)

“Since April all of the S&P 500 up move appears to have happened during extended market hours, while regular trading hours have on average acted as a small drag,”

Much of the gains in the European markets had come when their official trading sessions began, mirroring the strong performance of the S&P 500 when the U.S. stock market was shuttered. Whereas in Asia, markets tended to exhibit the biggest swings after regular hours.

By process of deduction, this suggested the most important news or flows likely took place during European regular trading hours.

The widespread suspicion that foreign investors were responsible for the divergence in the S&P 500’s performance between regular hours and after hours was misplaced.

Changes in Wall Street infrastructure meant US investors could keep trading even after the market closed at 4 p.m. ET.”