Stocks often rise the week of the Fed’s big Jackson Hole gathering. Don’t count on it this year.

The Nasdaq and S&P 500 dipped today, driven by tech stocks, as investors gear up for what Federal Reserve chair Jerome Powell will say about the path of interest rates at a key conference later in the week.

Wall Street's main indexes declined on Wednesday and the Nasdaq hit a two-week low as a rally in technology stocks cooled and caution prevailed ahead of the Federal Reserve's highly anticipated Jackson Hole symposium later this week After driving much of the market's recovery from the April selloff,