The most common and most likely answer to this crossword clue is the 4 letter word FIEF
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More clues leading to the result FIEF
Buddy explains!

The straight part
We know that "one’s personal area of control" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one’s personal area of control = fief.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 FIEF mean?
FIEF noun- An estate held by a person on condition of providing military service to a superior.
- Something over which one has rights or exercises control.
- An area of dominion, especially in a corporate or governmental bureaucracy.