The most common and most likely answer to this crossword clue is the 12 letter word PARTITIONING
I've seen this crossword clue in Financial Times
P
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T
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Buddy explains!
The straight part
We know that "Dividing up" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case dividing up = partitioning.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 PARTITIONING mean?
PARTITIONING verb- To divide something into parts, sections or shares
- To divide a region or country into two or more territories with separate political status
- To separate or divide a room by a partition (ex. a wall), often use with off
- The act or result of dividing into partitions; an arrangement of partitions.