The most common and most likely answer to this crossword clue is the 6 plus 3 plus 6 letter word STOCKS AND SHARES
I've seen this crossword clue in The Guardian
S
T
O
C
K
S
A
N
D
S
H
A
R
E
S
More clues leading to the result STOCKS AND SHARES
Buddy explains!
The straight part
We know that "Holdings of business" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case holdings of business = stocks and shares.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.