What a CFD is

The agreement itself 

Two parties agree on a reference price for a market that neither of them intends to hand over. One takes the side of the agreement that gains if the reference price is higher when the agreement ends. The other takes the side that gains if it is lower. Nothing is exchanged at the moment the contract opens. No shares move, no metal moves, no currency is delivered. When either party closes the agreement, the difference between the closing price and the opening price is multiplied by the size of the contract, and that amount of money passes from one side to the other. That is the entire instrument, and it is why the name is unusually literal: a contract, between two named parties, that settles a difference.

Almost everything else about a CFD follows from those two words. Contract means it is a private, bilateral agreement rather than a security that can be carried away, registered in a holder's name or sold on to a third party. Difference means the only thing that ever settles is the change in a price, so the question of who owns the underlying market never arises.

What the contract is written on 

A CFD has no price of its own. It borrows one. The market whose price the contract references is called the underlying, and it carries on existing entirely independently of the contract: a currency pair, a stock index, a barrel of oil, a listed share, an exchange traded fund. The underlying is quoted wherever it is normally quoted, and the CFD reads that quotation. Two parties writing a contract on the price of gold do not change the price of gold, and they do not remove an ounce of it from the market. The underlying markets a CFD can be written on at YAL are listed across the markets pages.

The second number in the agreement is its size, stated as a number of units of the underlying. Conventions differ by market and are published per instrument in its contract specifications: a standard lot of a currency pair is one hundred thousand units of the first currency in the pair, a shares CFD is conventionally written on a stated number of shares, and an index contract states a money amount per index point. Size is not a detail. It is one half of every calculation that follows.

Price multiplied by size gives the notional value of the contract, also called the contract value or the face value. Notional value is the number that profit and loss is calculated on. It is not the number that has to be funded, and the distance between those two facts is the most consequential thing in this lesson.

The arithmetic 

The calculation has two steps and no third one. The difference between the closing price and the opening price is taken, and it is multiplied by the number of units the contract covers. The result is an amount of money. It carries a sign, and the sign depends on which side of the contract is being calculated.

The symmetry is worth pausing on. The same contract, the same size and a move of the same distance in the opposite direction produce a result of the same magnitude with the opposite sign. Nothing in the structure of a CFD favours one side of it.

Profit and loss are calculated on the contract, not on the deposit 

A CFD does not have to be funded in full. The counterparty requires a percentage of the notional value to be posted and held for as long as the contract is open, and that percentage is the margin requirement. Posting margin is not paying for the contract. It is collateral held against the difference the contract may come to owe.

Because the difference is calculated on the full notional value while only a percentage of it has been posted, an adverse move is measured against the whole contract and not against the margin, so a loss can exhaust the margin entirely and is not limited to the amount deposited. A favourable move is measured on exactly the same basis and to exactly the same degree. Margin is the level at which a position becomes liable to be closed, not a boundary on what the arithmetic can produce.

Reading the fourth and fifth rows together makes the mechanism visible. The percentage move is a percentage of the notional value, not of the margin, so the money amount it produces bears no relationship to the size of the deposit at all. That is the mechanism by which a CFD position can produce a debit larger than the money placed behind it, and it is why the risk statement above is worded the way it is.

Who the other party is 

Every contract has two parties, and in a retail CFD the second one is the broker. The contract is written between the client and the firm. It is not routed onto an exchange and matched with another retail client, and no central clearing house stands between the two sides in the way one stands between the buyer and seller of an exchange traded future. That is what over the counter means in practice: bilateral, agreed between two named parties, and existing only between them. A firm may go on to hedge its own resulting exposure with a liquidity provider, but that is a second contract, and the client is not a party to it.

Two consequences follow, and both are checkable. First, a CFD can only be closed with the firm that wrote it. There is no secondary market for it, no transfer of an open position to another broker, and no certificate to move. Second, the financial standing of that firm is part of what a CFD holder carries, because the firm is the party that owes the difference whenever the contract settles in the client's favour. Regulators address the second point by requiring client money to be held apart from the firm's own money. YAL holds client funds in segregated accounts, as its regulator requires.

How this differs from buying the underlying 

Buying the underlying outright is a different transaction with a different result. The full purchase price is paid, title passes to the buyer, the asset settles into an account in the buyer's name, and it stays there until it is sold. Whatever comes with ownership comes with it: a place on a share register, a vote, the entitlements the issuer distributes. Once the trade has settled there is no counterparty left, because nothing further is owed by anybody.

A CFD produces none of that. No title passes, nothing settles into anyone's name, and the contract stays open, and owed, until it is closed. It also carries a cost that a purchase does not: because the full notional value is not funded, a position held past the daily cut off carries a financing adjustment for as long as it remains open. A CFD is a leveraged derivative contract. It is not a holding in a company or a stake in a fund, and the two are not interchangeable descriptions of the same thing.

How a contract ends 

Settlement is the moment at which the obligations under a contract are discharged. A CFD settles in cash and only in cash: the difference is calculated, the money moves, and the contract is extinguished. Closing a position is not selling something to a third party. It is entering the equal and opposite contract with the same firm, so that the two net to nothing and what remains is the difference between the price at which the first was opened and the price at which the second was written.

Most CFDs written on spot markets carry no end date and stay open until they are closed or until the margin held against them fails its requirement. CFDs written on futures inherit the calendar of the futures contract underneath them: they carry a stated expiry, on which they are closed at the prevailing price or rolled into the following contract, and that date is published in the instrument's specifications rather than chosen by either party.

Where practitioners disagree 

Two arguments about CFDs are genuinely unsettled, and a reader will meet both. The first is whether a CFD is usefully thought of as a wrapper around the underlying. One tradition treats it as exactly that: the same price, the same exposure, fewer administrative steps. Another points out that the wrapper changes the economics, because a financing adjustment accrues for as long as the contract is open while an outright holding carries no such line, so the two descriptions diverge the longer a position is held. Both are accurate over different horizons, which is why the disagreement persists rather than resolving.

The second concerns the counterparty. Because the firm writes the contract, a firm that retains the exposure rather than hedging it sits on the opposite side of its client's result, and critics of that model argue it is a structural conflict no disclosure removes. Firms answer that exposure is netted across a whole client book and hedged externally, and that regulators supervise execution and client money for precisely this reason. Neither answer settles the matter on its own. The honest position is that how a counterparty executes is a question worth asking of any firm, not one with a single industry answer.