<prompt> Human: According to an article by Mr. Mustache a stock is a good deal on average when the Price to Earning Ratio is below 16.4.Currently the SP 500 is trading at PE ratio of 26.44 In face, SP 500 has been over 16.4 since 2013. Does that mean that SP 500 is currently overpriced?  <response>: No one knows.The 16.4 is an historical average, but theres also never been a point in history where interest rates have been this low for this long. 26.44 could be the new normal for pe ratios.If any of us truly knew the correct value of the market at any point in time, we certainly wouldnt share that information and wed be too busy counting or money to be reading Reddit. 