It's entirely possible for me to borrow a share from you, (short) sell it back to you, and then for us to repeat that process an unlimited number of times, thereby shorting an unlimited amount of stock. This would be stupid since I'd owe you more stock than exists and you could set any price you wanted for them.
> In this case, they retain a fraction or none of their voting rights, I presume?
If you have a margin account and want to vote with your shares, you need to let your broker know prior to the vote, so they can be sure and not have your shares loaned out when they're figuring out everyone's voting shares.
Some time prior to 2010, I heard some heads rolled at my firm because such a request was screwed up for a major client, and they had fewer votes than expected for some important vote.
Individuals do not loan stock for shorting, generally. But they do sometimes have margin accounts (for unrelated reasons), and this allows the broker to loan their shares out without their knowledge. In this case, they retain a fraction or none of their voting rights, I presume?
Or must you manually opt in, to allow it to be loaned out for shorting?