The most common and most likely answer to this crossword clue is the 6 letter word SYNDIC
I've seen this crossword clue in The Guardian
S
Y
N
D
I
C
Buddy explains!

The straight part
We know that "business agent" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case business agent = syndic.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SYNDIC mean?
SYNDIC noun- A government official, a magistrate, especially one of the Chief Magistrates of Geneva.
- An agent of a corporation, or of any body of people engaged in a business enterprise; an advocate or patron; an assignee.