TeachMeFinance.com - explain Bucketing
Bucketing -- As distinguished from the manner in which a
bucket shop operates (see Bucket shop) bucketing of stocks
consists in sales by a broker (for his own account and risk)
against customers' purchases or purchases by the broker
against customers' sales.
Such a proceeding if not illegitimate is at least considered
irregular. The purpose may be to avoid the employment of
money in carrying (holding) stocks, but more often the Durpose
of the broker is to speculate against his customers or, in
speculative vernacular, to take the other end or other side of
the customers' trades. In either case ihe broker wins if his
customers lose or he loses if his customers win.