Perpetual Swaps: Futures That Never Expire

Key Takeaways

• A perpetual swap is a futures-like contract with no expiration and no final settlement.
• Funding payments tether the contract price to the underlying index price.
• The biggest mistake is ignoring funding cost, which compounds on leveraged positions over time.
• Perpetuals offer continuous leveraged exposure, so margin and liquidation rules drive your risk.

What It Is

A perpetual swap, also called a perpetual future, is a derivative that tracks an asset's price without ever expiring. dYdX defines it as a contract with no expiry date and therefore no final settlement or delivery.

Traditional futures expire on a set date, which forces traders to roll positions and creates a known convergence point with spot. Perpetuals remove that date. To stop the contract from drifting away from the real asset price, they use a recurring payment between traders called the funding rate.

The Intuition

A regular future converges to spot at expiry because that is when the contract settles. A perpetual has no expiry, so there is no natural force pulling it back to the underlying. Without a correction mechanism, the contract price could float far from the asset it is supposed to track.

Funding supplies that force. When too many traders crowd one side, the contract price drifts from the index price, the reference value of the underlying. Funding then charges the crowded side and pays the other, nudging traders to rebalance. The result is a contract that hugs spot continuously rather than only at a single settlement date.

The appeal is simplicity for leveraged speculation and hedging. You can hold a position as long as your margin supports it, with no roll dates to manage.

This convenience is also what makes perpetuals the dominant crypto derivative by volume. A trader who wants steady leveraged exposure does not have to track expiries, calculate roll costs, or reopen a position every month. The contract simply persists, and the funding mechanism quietly does the work that expiry once did.

How a Perpetual Swap Crypto Contract Works

A perpetual position has a few moving parts:

• Index price: the reference spot value of the underlying, usually from an oracle or a basket of exchanges
• Mark price: the value used to compute unrealized profit and liquidation, derived from the index to resist manipulation
• Margin: the collateral backing your leveraged position
• Funding: the periodic payment that ties contract price to index price

When the contract trades above the index, longs pay shorts, which discourages new longs and pushes the price down. When it trades below the index, shorts pay longs, which encourages buying and pushes the price up. dYdX states the goal plainly: funding keeps each perpetual market trading close to its oracle price.

The index price itself usually comes from an oracle that aggregates spot prices across several venues, which is what makes the mark price hard to manipulate with a single trade. Your unrealized profit and your liquidation level both track this oracle-derived mark, not the contract's own last traded price, so a brief wick on one venue should not by itself trigger a liquidation.

If your margin falls below the maintenance requirement, the position is liquidated. Because leverage magnifies both gains and losses, liquidation is the central risk of holding a perpetual.

Venues differ in how they run this. Order-book platforms such as dYdX match longs and shorts directly, while pool-based designs use a shared liquidity pool as the counterparty to every trader. The funding mechanism and liquidation rules are conceptually the same, but the exact parameters, including funding interval and margin tiers, vary, so the contract specification is required reading before you size up.

Worked Example

Suppose Bitcoin trades at 30,000 on the spot market, the index price. Strong long demand pushes the perpetual to 30,300, above the index.

You open a 1 BTC long with 10x leverage, posting 3,000 of collateral. Because the perpetual sits above the index, funding is positive, so as a long you pay funding to shorts. Using a Deribit-style example, if the 8-hour funding rate is 0.1 percent and you hold for 4 hours, the payment is about 0.0005 BTC for each BTC of position. That cost recurs every interval you stay long while funding is positive. Meanwhile a 3 percent drop in the mark price to about 29,100 would wipe out your 3,000 margin and trigger liquidation, since 10x leverage means a roughly 10 percent adverse move erases the position.

Common Mistakes

1. Ignoring funding cost. Funding is charged repeatedly, often every 8 hours. On a leveraged position held for days, a persistent positive rate can quietly erode a winning trade.

2. Confusing perpetuals with spot. A perpetual is a leveraged derivative with liquidation risk. Owning the perpetual is not the same as owning the asset.

3. Watching last price instead of mark price. Liquidation uses the mark price, which is anchored to the index. A brief wick on the contract's own order book may not match it.

4. Overusing leverage. High leverage shrinks the distance to liquidation. A position at 20x can be liquidated on a 5 percent move against you, before any thesis plays out.

5. Assuming all venues compute funding the same way. Funding intervals, caps, and the premium formula differ by platform. Read the specific contract specifications before sizing a position.

Frequently Asked Questions

What is a perpetual swap crypto contract in simple terms? A perpetual swap crypto contract is a leveraged bet on an asset's price that never expires. A recurring payment called funding keeps its price close to the real spot price.

How does a perpetual swap affect investment decisions? It lets you take leveraged long or short exposure without managing expiry dates, but funding cost and liquidation risk shape the true cost. Size positions to the margin you can afford to lose.

What is a real-world example of a perpetual swap? With Bitcoin spot at 30,000 and the perpetual at 30,300, a trader opens a 10x long. They pay periodic funding to shorts, and a roughly 10 percent adverse move would liquidate the position.

How can investors use perpetual swaps effectively? Use modest leverage, track the mark price for liquidation, and account for funding cost over your expected holding period. Hedgers can also use a short perpetual to offset spot exposure.

How is a perpetual swap different from a traditional future? A traditional future expires and settles on a set date. A perpetual never expires and instead uses funding payments to stay aligned with the underlying price.

Sources

1. dYdX Documentation. "Funding." https://docs.dydx.xyz/concepts/trading/funding
2. Deribit Insights. "Perpetual Swap Funding." https://insights.deribit.com/education/perpetual-swap-funding/
3. dYdX. "What are Perpetual Contracts?" https://www.dydx.xyz/crypto-learning/perpetuals-crypto
4. Cube Exchange. "What Is a Perpetual Futures Contract?" https://www.cube.exchange/what-is/perpetual-futures

Disclaimer

This article is educational content only and is not financial advice. Nothing here is a recommendation to buy, sell, or hold any security. Consult a licensed advisor before making investment decisions.