Yes it does. But remember brokerage have SIPC insurance which protect you from the first $250,000 worth of loses if you brokerages goes broke. Many brokerage carry additional coverage, so for example Schwab has Llyods of London policy which provide insurance for up to $1,150,000 in cash.
If you have more than $250,000 in a bank than in theory you could lose some of the money, because your deposits are pooled with other depositors. In practice customers deposits and customers securities are the first thing to be paid in the even of bankruptcy, so it is very rare for anybody to lose money.
Even the MF Global scandal where $1.5 billion when missing for a while, eventually ended up in the customers being made whole.
