Goldman, Morgan Scrap Wall Street Model, Become Banks in Bid to Ride Out Crisis:
"It had become increasingly clear to Fed officials in recent days that the investment-banking model couldn't function in these markets. Investment banks depend on short-term money markets to fund themselves, but that had become increasingly difficult, particularly in the wake of the collapse of Lehman Brothers. As bank holding companies, Morgan Stanley and Goldman Sachs will be allowed to take customer deposits, a potentially more stable source of funding."
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The ascendancy of commercial banks largely reflects their use of customer deposits to fund much of their business. Retail depositors tend not to yank their money out, even in turbulent times, thanks to backing by federal deposit insurance. Even at Washington Mutual Inc., a Seattle thrift-holding company battered by mortgage losses, deposit levels are basically unchanged so far this year