It's been a huge change for the mega-caps over the past decade, after they were greatly overvalued in the dot-com bubble era. As Lim points out, in 2000, the average price-to-earnings ratio for the mega-caps reached 33. Now that number is all the way down to 13 - and with midcaps at 16 and small-caps at 20, the big stocks look like a relative bargain.