I have loaned shares out from time to time and it has always been an on demand arrangement. I don't think it is likely that many people would lend shares for a set amount of time as there is alot of flexibility cost involved that doesn't exist if you loan them on demand .
When I have lent shares out my broker gave me a letter of credit from one of the major financial institutions to cover the loaned stock value.
When I have lent shares out my broker gave me a letter of credit from one of the major financial institutions to cover the loaned stock value.

