TD Bank. It was widely reported that one Canada's biggest banks became the most "shorted" in the world (e.g., https://financialpost.com/fp-finance/banking/toronto-dominion-bank-biggest-shortLinks to an external site.). What is a short-sale? How does it work and why is it generally considered to be a risky endeavour? Why might there be such a large amount of short selling related to TD bank and should investors (and Canadians) be concerned?