September is a 'rotten' month for stocks and this year, high bond yields and inflation top the list of risks, Ed Yardeni says

• US stocks are one week into what's historically been their worst month of the year, in what is known as "The September Effect".
• The S&P 500 is currently down about 1% so far this month. 
• Market veteran Ed Yardeni has highlighted some of the key risks facing investors this time around.

US stocks are one week into what's historically been the worst month of the year for the market. 

Since 1945, the S&P 500 has slid 0.7% on average in September, data from CFRA Research shows. This year, it's down by about 1% so far in the month.

Ed Yardeni, president of Yardeni Research, wrote in a Tuesday note to clients that September is "widely viewed as a rotten month for stocks", and listed the key risks facing investors this time around.