The most common and most likely answer to this crossword clue is the 5 plus 8 letter word STOCK EXCHANGE
I've seen this crossword clue in The Times
S
T
O
C
K
E
X
C
H
A
N
G
E
More clues leading to the result STOCK EXCHANGE
- Conventional argument in place of financial trading
- Standard disagreement where securities are traded
- Make money here, swapping cows for sheep?
- Cliched remarks where capitalists congregate
- Normal conversation in place of business?
- Standard conversation in market with traders
- Standard conversation offering place for investors
Buddy explains!

The straight part
We know that "where securities are traded" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case where securities are traded = stock exchange.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.