The most common and most likely answer to this crossword clue is the 6 letter word SHEKEL
I've seen this crossword clue in Independent
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Buddy explains!
The straight part
We know that "Currency used in controversial bank settlements?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case currency used in controversial bank settlements? = shekel.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 SHEKEL mean?
SHEKEL noun- A currency unit of both ancient and modern Israel.
- (often antisemitic) Money, especially that purportedly owned or distributed as bribes by Jewish elites.
- An ancient unit of weight equivalent to one-fiftieth of a mina.