The most common and most likely answer to this crossword clue is the 6 letter word INDIES
I've seen this crossword clue in The Daily Telegraph
I
N
D
I
E
S
Buddy explains!

The straight part
We know that "Record companies" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case record companies = indies.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 INDIES mean?
INDIES noun- An independent publisher.
- A work released by an independent publisher.
- A type of rock music, generally soft-style without screaming or aggression, mixed with synthesized music and electronic.
- A person who listens to indie music and follows indie fashion.
- An independent entity.
- Cars designed to meet the rules on the Indianapolis 500 car race.