A short sale of a stock is where the seller actually owns the stock, but does not want to close out the position.

A situation in which a person is both long and short in the same security at the same time in his account, a practice usually employed to defer tax liability on capital gains.

Shorting against the box means short selling securities that you already own. This results in a neutral position where your gains in a stock equal the losses. Investors short against the box in order to delay a taxable event; for example, delaying capital gains until the next year.

Short Bias Short bonds

Short book Short exempt