Trading index CFDs: what you are actually buying
An index CFD is not the index, and it is not a share in anything. Understanding what sits behind the quote explains the financing charges, the gaps and the dividend adjustments.
Key takeaways
- – A CFD is a contract with your broker, not ownership of anything in the index
- – Cash indices carry daily financing; futures-based contracts carry a roll instead
- – Dividend adjustments and out-of-hours pricing surprise people who assume the quote tracks the cash index exactly
A contract for difference on an index settles the difference between the price when you open and the price when you close. You never own the underlying shares, you have no voting rights, and you receive no dividends. What you have is an agreement with your broker, which is why the broker’s terms matter as much as the market does.
Cash versus futures-based contracts
Brokers usually offer two shapes. A cash index contract has no expiry and is financed daily: you pay or receive an overnight charge derived from a reference interest rate plus the broker’s markup. Holding a long position for months means paying that charge every night, which quietly erodes returns on slow-moving positions.
A futures-based contract has an expiry and no nightly financing, because the cost is already embedded in the futures price. Instead you face a roll when the contract expires, and the price gap between the expiring and next contract is adjusted for – usually through a cash adjustment on your account.
Neither is better in the abstract. Cash contracts suit short holding periods; futures-based contracts suit longer ones.
Dividend adjustments
When constituent shares go ex-dividend, the cash index mechanically drops. A CFD provider adjusts for this so you are neither rewarded nor penalised: long positions receive a credit, short positions pay. If you have ever seen an index open sharply lower with no news, a cluster of ex-dividend dates is usually the explanation.
Out-of-hours pricing is a different market
Many brokers quote index CFDs long after the underlying exchange closes. That price is derived from futures and from the broker’s own book, not from live share trading. Spreads widen, depth thins, and a position stopped out at three in the morning may have been removed by a price that no cash market ever printed.
What to check before trading one
- Which contract type you are trading, and the financing or roll cost that comes with it.
- The contract size per point, so position sizing is based on the right notional.
- Trading hours, and what happens to your stop outside the cash session.
- How the broker handles dividend adjustments and index rebalances.
Read our broker due-diligence checklist before funding any account, and size positions with the position size calculator.
