if you want to have it heard by people that can see you only, and not by say hidden thieves and invised crits then just say it, don't yell like this:
<banker> withdraw 500000 ; " money's up!
talk prefix is "
I always found it humorous that people doing transfer in bank would yell through out the whole town about it

PS
in <banker> you have to use actual NPC's name just "banker" will not work.
deposit:
<banker> deposit 500000 ; @ money's in-and-out!
or
<banker> deposit 500000 ; " money's in-and-out!(hush-hush)