Not too sure how may Opes Prime clients received a collateral margin equal to or higher than their loaned shares. If they did, no one would be currently out of pocket as they would have the value of their lodged collateral sitting in their bank.
What is securities lending?
Securities lending is the temporary transfer of a security by its owner to another investor or financial intermediary. Once the securities have settled, the title and voting rights are transferred to the borrower, who can sell or re-lend the borrowed securities during the life of the loan. In return, the borrower agrees to return the loaned securities, secure the loan with collateral of equal or greater value than the loaned securities, and pay any user fees (implicit or explicit), and remit to the lender any dividends, coupon interest or other distributions that occur during the time the securities are on loan.