First Trust Multi Cap Growth AlphaDEX Fund (the Fund) is an exchange-traded fund. The Fund seeks investment results that correspond generally to the price and yield of an equity index called the Defined Multi Cap Growth Index (the Index). The Index is an enhanced index created and administered by Standard & Poor’s, which selects stocks from the S&P Composite 1500/Citigroup Growth Index. Standard & Poor's constructs the Index by employing the AlphaDEX stock selection methodology to rank the stocks from the three component indices that comprise the S&P Composite 1500/Citigroup Growth Index, which are the S&P 500/Citigroup Growth Index, the S&P MidCap 400/Citigroup Growth Index and the S&P SmallCap 600/Citigroup Growth Index. The Index is reconstituted and rebalanced quarterly. The Fund’s investment advisor is First Trust Advisors L.P.