"The basic form of short selling is selling stock that you borrow from an owner and do not own yourself. In essence, you deliver the borrowed shares. Another form is to sell stock that you do not own and are not borrowing from someone. Here you owe the shorted shares to the buyer but "fail to deliver." This form is called naked short selling. These short sales are almost always done only by options market makers because they allegedly need to in order to maintain liquidity in the options markets. However, these options market makers are often the brokers or large hedge funds, who abuse the options market maker exemption. (For more, see How To Work Around A Market Maker's Tricks.)

Shorting Without Failing to Deliver There is another form of short selling, which I describe as synthetic short selling. This involves selling calls and/or buying puts. Selling calls makes you have negative deltas (a negative stock equivalent position) and so does buying puts. Neither of these positions requires borrowing stock or "failing to deliver" stock.

A collar is nothing more than a simultaneous sale of an out-of-the- money call and a purchase of an out-of-the-money put with the same expiration date. Another way to short sell is to sell a single stock future, which is equivalent to naked short selling. No shares are borrowed, however, and no shares are failed to deliver..."

"... There are similar future transfers if you have sold calls or sold single stock futures. When you buy puts and fully pay for them, there are none of these money transfers after the purchase, although the value of your account certainly fluctuates as the value of the puts fluctuates.

All of the above ways to obtain negative deltas cause pressure on the value of the stock similar to how straight sales of long stock puts pressure on the price of the stock..."

Continued via the link above which is well worth the read. All things considered, we are ultimately talking about derivatives and derivatives of derivatives.