Did Alibaba's IPO signal a top in the stock market?

``These numbers are painting a picture of extraordinary divergence, in Martin's opinion, indicating a very unhealthy market in which the bull market is relying on the strength of a fewer and fewer number of very large-cap stocks. He says, whenever in the past you have had a new high in the large-cap indexes and net new lows among secondary stocks, "you invariably have been at important market tops."''