There is no guarantee that all eligible shares in a given account will be loaned through the Stock Yield Enhancement Program as there may not be a market at an advantageous rate for specific securities, MEXEM may not have access to a market with willing borrowers or MEXEM may not want to loan your shares.
Clients carrying financing deficits are subject to having stock amounting to 140% of the deficit un-segregated, chosen at the discretion of the broker, and therefore ineligible to lend as part of the SYEP.
Please refer to: the FAQ for additional information.