Have the markets reached a top? 

Disagreeing with his fellow Trading Strategies roundtable panelist Stephen Guilfoyle on the state of the market in September, David Yoe Williams, a commodities and gold expert, said the market has reached dangerous highs. "The bigger they are, the harder they fall," Yoe Williams said. 

"We're up at these lofty levels, and God bless it; I would be very careful," Williams said. 

Though he said that a fall might not happen in September, Williams said that he expects to see a "significant" decline in the market before December. 

In the current low volatility environment, it's been 19 months since the S&P 500 sold off 10 percent. Williams said that one percent isn't significant and that even 10 percent is barely significant, and it would take a fall of between 15 and twenty percent to be considered notable. 

Should you be prepared for the market to fall with the leaves?

Check out more of our September Trading Strategies special report below:

• Stephen "Sarge" Guilfoyle: Why I Love Apple, Nvidia and These Other Stocks for September

• Doug Kass: Why You Must Immediately Short Amazon, Starbucks, Disney and 3 Other Stocks

• Scott Gamm: This Analyst Loves Citigroup, Intel and Total for September

• Jonathan Heller: These 5 Amazing Stocks to Own for the Rest of 2017 Aren't for the Faint of Heart

• Jim "RevShark" DePorre: Is a Nasty Market Correction Coming in September?

• Peter Tchir: 5 Things Smart Investors Should Do in September

• Our complete Trading Strategies special report

Watch More with TheStreet:

• Get Your First Look at the Futuristic Apple iPhone X

• The Costliest Countries to Buy an iPhone

• Apple Just Gave a First Look at Its New Campus

• Nascar Champ Danica Patrick -- 'I Get Paid Better Than Most Men in My Field'