The most common and most likely answer to this crossword clue is the 8 letter word PASSBOOK
I've seen this crossword clue in The Daily Telegraph
P
A
S
S
B
O
O
K
Buddy explains!
The straight part
We know that "Trading record" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case trading record = passbook.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 PASSBOOK mean?
PASSBOOK noun- A customer's record of deposits and withdrawals from a savings account at a bank, typically recorded in a small booklet. The bank keeps its own record, which is final in any dispute.
- A book that passes between a trader and a customer, used to record credit purchases.