September has a well-earned bad reputation with S&P 500 investors. But some think signs point to a better September this year.

September is the S&P 500's weakest month and the Fed decision falls on the day the index has historically peaked. LPL's Adam Turnquist on what's at stake.

September has a well-earned bad reputation with S&P 500 investors. But some think signs point to a better September this year.