The most common and most likely answer to this crossword clue is the 5 plus 3 letter word TRADE GAP
I've seen this crossword clue in The Guardian
T
R
A
D
E
G
A
P
More clues leading to the result TRADE GAP
- Old revolutionary caught by trick, a financial problem
- Call for rapid movement over deficit
- Publicity, say, in region reversed business deficit
- Call for small missile to tip unfavourable balance
- Traffic in front of clothes store – a matter of concern to business
- Old, upset, taken in by trick producing negative balance
- See servant dash up to provide a bit of business information
- Call for rapid movement over Brexit problem?
- The difference between imports and exports
- Commercial break making a difference?
Buddy explains!

The straight part
We know that "unfavourable balance" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case unfavourable balance = trade gap.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.