Short Selling on the Exchange: A Securities Loan, Not a Bet on a Fall

A short (short position) is the sale of a security you do not own: the investor borrows it from the broker, sells it straight into the order book at the market price and undertakes to return the same security later — the security itself, not money. The result of the trade is the difference between the sale price and the buy-back price, less costs. "Short" describes neither a mood nor a forecast but a legal structure: a securities loan inside a margin agreement, in which the broker acts as the lender and the assets you bought earlier serve as collateral.

How it works, step by step

Step 1. You place an order to sell a security that is not in your account. The broker sees a negative balance in that position and automatically provides a loan — out of its own securities or those of other clients who have allowed them to be used.

Step 2. The order goes into the exchange order book and is executed against a buyer on the other side. For the market this is an ordinary trade: whoever bought {{instrument:SBER}} from you does not know, and has no need to know, whether the position was long or short.

Step 3. The proceeds of the sale are credited to the account, but you cannot dispose of them freely — they are held as collateral against the outstanding debt.

Step 4. The position is closed by buying back the same security in the same quantity. The security is returned to the lender, the debt is repaid and the financial result is locked in.

The key difference from an ordinary trade: a long position is closed when you choose, while a short position is closed when you choose or when the broker demands it.

Where the security comes from and what you pay for

The loan is not free. If the position is carried overnight, the broker rolls it over through REPO trades and charges a fee for the use of the security. The rate is not a market constant: it is set out in the tariff of the particular broker and changes depending on how scarce the security is. For the same reason, each broker has its own list of instruments available for shorting, and that list can shrink without warning — sometimes there is simply nobody to borrow a rare security from.

On top of this come the usual costs of a trade: the broker's commission and the exchange fee, and they are paid twice — on the sale and on the buy-back.

A separate item, and the most frequently forgotten: if a dividend record date falls while your short position is open, the broker debits the amount of the dividend from your account. The logic is simple — the rightful owner of the borrowed security must not lose out because you sold it, so you are the party that compensates the payment. It is worth checking the nearest dates in advance against the payment calendar: {{dividend_calendar|limit=5}}. With bonds, the same story applies to accrued coupon interest.

Collateral, margin and the margin call

The broker cannot allow the debt to grow larger than the value of your collateral. That is why every security in the portfolio is valued at a risk discount, and two levels are calculated continuously for the portfolio: initial margin (how much is needed to open or increase a position) and minimum margin (the threshold below which the broker steps in). Risk rates are set by the clearing organisation and refined by the broker, while the amount of leverage available also depends on the risk category assigned to you — standard, elevated or special.

When the value of the portfolio falls towards the minimum margin, a demand to top up the account arrives. If you do not do so, the broker closes the position by force — at whatever price is in the order book at that moment, not at the price that seems fair to you.

What a short is not

A short is not the sale of your own security. If you sell what you bought earlier, there is no loan, no collateral is calculated and no carry fee is charged.

A short is not the same thing as buying a put option or selling a futures contract. The economic effect is similar, but the risk is built differently: with an option the buyer's loss is limited to the premium paid, and with a futures contract there is no securities loan and no dividend compensation — it has its own system of initial margin.

A short is possible only where there is central clearing and securities lending. On the over-the-counter market a trade is concluded directly with the counterparty, and the mechanics of short selling in their familiar form do not exist there — see also the term over-the-counter market.

Finally, "short" does not equal "falling market". A short position can be part of a pair trade or a hedging structure in which the direction of the index is not the bet at all.

What you need in order to short

You need a brokerage account with margin trading enabled — an ordinary account does not provide it by default. How the account itself is set up and what is signed when it is opened is covered separately: brokerage account. Before entering into uncovered trades, a non-qualified investor is required to pass a test — this requirement has been in force since 2021 and is lifted only by qualified investor status.

An honest caveat: specific borrowing rates, discounts on securities and the list of instruments available for short selling are not given in this article — these are not market values but the terms of your agreement with the broker. They have to be looked up in the tariff and in the appendix to the broker's regulations.

What to check before opening a position

Before selling short, it makes sense to look at three things: whether the security is available for shorting at your broker and at what rate; whether a dividend record date or a corporate event is coming up in the near future; and whether there is enough liquidity in the order book to exit without slippage. The profile of a particular security is conveniently viewed in the stocks section, and unfamiliar words in the glossary.

One more property worth keeping in mind ahead of time: the long-term holding relief under Article 219.1 of the Tax Code of the Russian Federation is built around the period for which a security is held. It does not apply to a short position — by definition, there is no holding there.