what 10 stocks are most levered to margin debt?

Answer 1

Margin is against your entire account and not against a specific security. It would be difficult at best to determine this and only the aggregate transactions of the brokers would create such a record and they are not talking.

What you may do as a substitute is find the 10 stocks with the narrowest bid-ask spread divided by the bid. These are unusually liquid and would likely have margin being created in their transactions.