The most common and most likely answer to this crossword clue is the 6 letter word USURER
I've seen this crossword clue in Financial Times
U
S
U
R
E
R
More clues leading to the result USURER
- One taking interest in the solver’s texting, indeed!
- Old city stores certainly a source of interest
- One taking a lot of interest in American rivers
- United more certain he’s a rip-off merchant
- More confident after last item on menu is shark …
- Shylock, perhaps, firm in old city
- Central courts cover confident cupidinous capitalist!
- Leader of coup deposing prince and extortionist
- He’s taking interest in United, growing more confident
- Money handler certain to go into the city
Buddy explains!

The straight part
We know that "He’s taking interest" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case he’s taking interest = usurer.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 USURER mean?
USURER noun- A person who loans money to others and charges interest, particularly at an illegal, exorbitant, or unfair rate.
- Specifically, a male usurer.