What is a zero-sum game?
A zero-sum game is a situation where whatever a side gains is lost by the other side, so the total gain across all participants is zero.
The term comes from game theory. The formal definition: a game is zero-sum when, for every possible outcome, the payoffs of all players add up to zero. A broader form is a constant-sum game, where the payoffs always add up to the same fixed total. Strategically, a constant-sum game behaves the same way.
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Zero-sum game in trading
The idea fits best with derivatives. These are contracts whose value comes from another asset (see derivatives). Examples are futures, a forward contract and a call option. Every contract has a buyer and a seller. Any price change moves value from a side to its counterparty. No new value is created inside the contract.
Zero-sum game example (hypothetical)
Trader A buys a gold futures contract. Trader B sells the same contract to A.
- If the gold price rises, A's contract gains value. B loses exactly the same amount.
- If the price falls, B gains what A loses.
- Before costs, A's result plus B's result is always zero.
Now add costs. Each trader pays a spread, a commission or financing (see swap fees). These payments go to the broker, the exchange or the clearing house. They do not go to the other trader. After costs, A's and B's results together come to less than zero. For traders as a group, the game is negative-sum.
To see what a price move and costs mean in money for a given position size, use the tools on the calculators page.
Edge cases experienced traders should know
- Shares are not zero-sum over time. Companies can grow profits and pay dividends. Holders as a group can then gain without a matching loser. A single trade between a buyer and a seller is still a transfer between them.
- Hedging changes the picture. A farmer or importer who hedges may accept a loss on the contract to fix a price. In money terms the contract is still zero-sum. In usefulness, both sides can be better off.
- Forex and CFDs. With CFDs, the trader's counterparty is often the broker itself, or the broker passes the risk on to the market (see A-book and B-book). In the first case, the client's gain is the broker's loss before costs.
- Arbitrage and market-making earn from price differences and spreads. Part of what other traders lose to costs becomes income for these participants (see arbitrage and dealer).
Where the term appears
Trading platforms do not label anything as "zero-sum". You see it indirectly: the profit and loss on a long position mirrors the loss and profit on the opposite short position of the same size.
The phrase is common in financial news and research reports. It usually appears in debates about whether futures, options or short-term trading create value. Regulators and educators use it to explain why most retail traders lose money after costs.
Leveraged forex and CFD trading can lose money fast, and costs make the odds worse. Read risk management before trading real funds.
Related terms
Frequent questions
What is the zero sum game meaning in simple words?
A side's gain equals the other side's loss, so the total across everyone is zero.
Is trading a zero-sum game?
Derivatives trading is zero-sum before costs. After spreads, commissions and swaps it is negative-sum for traders as a group. Long-term share ownership is not zero-sum.
Is the stock market a zero-sum game?
No. Company earnings and dividends can raise the total value held by investors. Individual trades between buyers and sellers are transfers.
Why does it matter to a retail trader?
In a zero-sum market, a gain must come from another participant, and costs reduce the total. Gains are never guaranteed, and losses can be large, especially with leverage.