Right, and the lenders are typically institutions who are holding the stock for reasons other than speculation (e.g as part of a tracker fund for clients) and a

Right, and the lenders are typically institutions who are holding the stock for reasons other than speculation (e.g as part of a tracker fund for clients) and are simply attempting to extract more value from their holding. No point it sitting there in your depot account if you can get paid a few % by lending it.