The latter included Microsoft, Cisco, Dell, Intel, GE, Yahoo, AIG and Juniper Networks---plus four others which didn't survive (Lucent, WorldCom, Global Crossing and Nortel).
Together they represented a classic blow-off top in the context of a central bank corrupted stock market. When the bubble neared its asymptote in early 2000, the $3.8 trillion of market cap represented by these 12 names was capturing most of the oxygen left in the casino. That is, the buying frenzy had narrowed to a smaller and smaller group of momo names.
That severe concentration pattern was starkly evident during the 40 months between Greenspan's December 1996 "irrational exuberance" speech and April 2000 (when he told the Senate no bubble was detectable). In that interval, the group's combined market cap soared from $600 billion to $3.8 trillion.