The most common and most likely answer to this crossword clue is the 4 letter word BALE
I've seen this crossword clue in Financial Times
B
A
L
E
More clues leading to the result BALE
Buddy explains!

The straight part
We know that "bound bundle" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case bound bundle = bale.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 BALE mean?
BALE noun- Evil, especially considered as an active force for destruction or death.
- Suffering, woe, torment.
- A large fire, a conflagration or bonfire.
- A funeral pyre.
- A beacon-fire.
- A rounded bundle or package of goods in a cloth cover, and corded for storage or transportation.
- A bundle of compressed wool or hay, compacted for shipping and handling.
- A measurement of hay equal to 10 flakes. Approximately 70-90 lbs (32-41 kg).
- A measurement of paper equal to 10 reams.
- To remove water from a boat with buckets etc.