Professor Elam

The crash of 1972-74 eliminated lots of Wall Street firms from 'the business.'  Goodbody and Co, a partnership was no more. Merrill absorbed White Weld and thereby entered the real investment banking business. And upstart Shearson omigosh, gobbled hallowed Loeb Rhoads. Francis I. duPont became DuPont Glore Forgan and then Ross Perot gained control and then it was DuPont Walston and then, well, it was no more. Paine Weber.  Smith Barney has been owned by several firms. In Texas smaller firms like Underwood Nuehaus in Houston merged with other firms. 

Eventually even First Boston, always on the first line of an underwriting tombstone, was taken by Credit Suisse but that took until 1988. Paine WEber became part of UBS in 2000. And so Blackrock becomes a new serious player. They deal in other people's wealth management, a distinct difference from Goldman or Morgan. Merrill Lehman and Bear brought on their own demise by playing the markets with leverage instead of brokering the market for clients, uh oh. Read this interview on why Blackrock is successful.