NEW YORK (TheStreet) -- The S&P 500 is slightly lower Tuesday following the mixed earnings results companies have reported so far. If earnings come in lower on the year, then the overall market is trading too high, Ritholtz Wealth Management CEO and co-founder Josh Brown and hedge fund manager David Einhorn agreed on CNBC's "Fast Money Halftime Report." The median S&P 500 stock trades at 21 times earnings, amid weakening economic data and declining earnings estimates, Brown added.