The most common and most likely answer to this crossword clue is the 10 letter word ENDOWMENTS
I've seen this crossword clue in The Guardian
E
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More clues leading to the result ENDOWMENTS
Buddy explains!

The straight part
We know that "Settlements" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case settlements = endowments.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 ENDOWMENTS mean?
ENDOWMENTS noun- Something with which a person or thing is endowed.
- Property or funds invested for the support and benefit of a person or not-for-profit institution.
- Endowment assurance or pure endowment.
- A ceremony designed to prepare participants for their role in the afterlife.