Just call us Bond. Amortized bond.
Over 700 finance terms, Shmooped to perfection.
Sounds exactly like what it is: a transaction that isn't authorized.
An unauthorized transaction happens when your broker makes a trade in your account without you giving the thumbs up. Really nasty brokers can even set up fake mailing addresses so that you never get the letters about the trades, so you don't know about the extra activity on your account.
Needless to say, it's illegal. Like... very illegal.