The most common and most likely answer to this crossword clue is the 12 letter word CONGLOMERATE
I've seen this crossword clue in The Guardian
C
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More clues leading to the result CONGLOMERATE
- Left in Congo with this writer, assess business organisation
- Millions investing in one cartel go wild for group of companies
- Group of companies, not large, come for training
- Industrial group needs answer to puncture awful recent gloom
- Business group needing a long-term CEO to be sacked
- Lake in African republic only occupied by a tense business group
- Get clean room organised for business group
- Somehow get clean room for corporation
Buddy explains!

The straight part
We know that "Group of companies" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case group of companies = conglomerate.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 CONGLOMERATE mean?
CONGLOMERATE noun- A cluster of heterogeneous things.
- A corporation formed by the combination of several smaller corporations whose activities are unrelated to the corporation's primary activity.
- A rock consisting of gravel or pebbles embedded in a matrix.
- To combine together into a larger mass.
- To combine together into a larger corporation.
- Clustered together into a mass.
- Composed of fragments of rock, pebbles, or stones cemented together.