Honey, baby, cookie, lovey - that's the hello of a different kind of agent, the guy in the bright yellow suit with awesome Hollywood hair.
But a broker agent or agency broker is just an agent for a fund, or typically any large agency, which places big block orders on exchanges - the key issue is that the agent must try to get his client the best prices. Lots of ways to corrupt the system - see front running and kickbacks for the gory details.
Broker-dealers are self-dealers - they buy on behalf of themselves. They aren't agents and they are obligated only to fulfill orders they commit to executing.