The most common and most likely answer to this crossword clue is the 11 letter word CORPORATION
I've seen this crossword clue in The Daily Telegraph
C
O
R
P
O
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A
T
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N
More clues leading to the result CORPORATION
- Fat tummy, big concern
- Chapter on poor reorganisation helping large firm
- Company expanded central reserves?
- My work is about helping big business
- Evidence of excess in big business?
- Officer almost into rebuilding firm
- Chapter on exploitation of poor helping large firm
- Large company gathering in a root crop
- Statesman’s concern with extra weight carried?
Buddy explains!

The straight part
We know that "Large company" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case large company = corporation.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 CORPORATION mean?
CORPORATION noun- A body corporate, created by law or under authority of law, having a continuous existence independent of the existences of its members, and powers and liabilities distinct from those of its members.
- The municipal governing body of a borough or city.
- In Fascist Italy, a joint association of employers' and workers' representatives.
- A protruding belly; a paunch.