Exactly Mac. Academic research on the practice of legal short selling in the marketplace has nothing to do with malicious sellers who spread falsities or illegal short sellers fueling a stock slide. IMHO
That is true, however the prevalence of naked short selling is now only a tiny fraction of what it was. Reg SHO diminished it substantially, and Rule 204T which came out in 2008 reduced fails-to-deliver by over 85%.
Rule 204T requires that any participant of a registered clearing agency has to quickly close out fails-to-deliver.
In a nutshell, if someone shorted "naked" and you were the buyer in the market, your shares wouldn't be delivered. It's an FTD (fail to deliver) - you wouldn't have the shares, wouldn't be able to vote the proxy and so on.
Thus for every supposed "naked" short, there is a naked long. So tell me what ANY longs have bought shares in the market and having been sitting there for months or even years without the shares showing up and just shrugging about it?
fails to deliver data is available daily. For ANY it is negligible.
I'm also not sure efficiency is the only value we wish to inculcate. Mass arrests by the police in big cities are efficient insofar as many potential criminals are frequently incarcerated and crime rates decline, but the practice is incompatible with other values such as human rights.