Perp DEX Explained: How Funding Rate, Liquidation and Taxes Work on Perpetual Futures

Trading in perpetual contracts is shifting away from exchanges that hold a customer account for you and towards venues where you sign every order with your own wallet. These venues are called perp DEX. Anyone reading the abbreviation for the first time will usually find either marketing copy or documentation written for developers. This article sits in between: it explains what happens when you open a position there, which costs accrue while it runs, and where the construction breaks.

One point up front: a perpetual is a leveraged product. The figures below come from the public documentation of individual venues and describe their own rules, not an industry standard.

Perp DEX vs Crypto Exchange: The Difference in Structure

A perp DEX is a venue for open-ended futures contracts that works without a customer account in the traditional sense. You do not place a deposit with a company that holds it for you. Instead you post collateral into a smart contract and authorise every action with your own key. No central operator runs an account in your name, and as a rule nobody can bar you from trading. That sounds like a detail of custody, but it has consequences: there is no deposit protection, no complaints body and in many cases no one who will unwind a faulty trade.

The Components

At its core, every perp DEX consists of something that establishes a price, a mechanism that brings buyers and sellers together, and a rule that closes positions once the collateral posted no longer covers them. All three are attack surfaces, and the incidents of recent weeks hit exactly these parts.

Perpetual Futures: The Contract Without an Expiry Date

A conventional future has an expiry day. On that day it settles, the contract ends, and anyone who wants to stay invested has to roll into the next contract. A perpetual drops that expiry day. The position runs until you close it or until it is liquidated.

This creates a problem that immediately becomes the largest cost factor. A future converges on the spot price automatically as expiry approaches, because settlement happens at the end, either physically or in cash. A contract without an expiry day has no such anchor. In theory it could drift arbitrarily far from the actual market price. The funding rate exists to prevent that.

Funding Rate: What an Open Position Costs You Over Time

The funding rate is a payment that flows between the two sides of the market at regular intervals. If the contract trades above the reference price, the long positions pay the short positions; if it trades below, the payment runs the other way. That incentive is what pulls the contract back towards the market price.

What this looks like in concrete terms can be read in the documentation of Hyperliquid, one of the larger venues of this kind. There, funding is settled hourly, each time at one eighth of the calculated eight-hour rate. The payment runs directly between traders, and the venue keeps none of it.

What Goes Into the Formula

The rate is made up of two components. One is the premium index, meaning the measured gap between the contract price and the reference price. The other is a fixed interest component of 0.01 percent per eight hours, which works out at 0.00125 percent per hour or roughly 11.6 percent a year, and goes to the short side. The adjustment between the two is capped at plus/minus 0.0005. At the top end, the same documentation sets a hard limit of four percent per hour.

Those four percent are the number worth remembering. They are never reached in normal operation. In a disorderly market where everyone sits on the same side they can be reached, and holding a position then costs you a substantial share of your collateral within a single day, without the price having moved against you at all. Work that through for your intended position size before you open it.

Mark Price and Oracle: Which Price Decides Your Position

A perp DEX carries at least two prices: the one currently being traded, and the mark price, which determines whether your position is liquidated. The two can drift apart.

The mark price is deliberately not derived from the venue's own order book alone, because a thin book can be moved with very little capital. Hyperliquid describes it as a combination of external prices from centralised exchanges and the state of its own book; at GMX, according to the project documentation, the price comes from aggregated exchange data. The intention is that a liquidation should not be triggered by a brief price spike on a single venue.

That is the theory. In practice the price source is one of the most vulnerable points in the entire construction. Anyone who manipulates the price a protocol holds to be true has no need to attack the contracts themselves. Exactly that happened at Ostium in late July, where our own reporting found the incident to be an attack on the price feed, while the trading logic itself remained intact.

Liquidation: The Price at Which Your Position Is Force-Closed

When you open a position you post initial margin. It follows from position size times mark price, divided by the leverage you choose. While the position runs, a lower threshold applies, the maintenance margin. Once your capital falls below it, the position is closed.

Hyperliquid sets the maintenance margin at half the initial margin at the highest leverage permitted for each asset. Expressed as a percentage, it ranges there from 1.25 percent for assets with 40x leverage to 16.7 percent for assets with 3x leverage. The second figure is the more instructive one: where a venue permits little leverage, it demands a considerably thicker buffer, because it regards the market as less resilient.

When the Buffer Is Not Enough

In the first step the system tries to unwind the position through ordinary market orders in the book. If that does not suffice and capital falls below two-thirds of the maintenance margin, backstop liquidation takes over: the position passes to a liquidator vault, and the maintenance margin is not refunded. Put differently, in that case you lose more than the arithmetic distance to the liquidation price.

In our assessment this is the point most often underestimated. The liquidation price looks like a boundary at which the matter ends; in fact that is where the unwinding begins, and how expensive it gets depends on the liquidity available in that moment.

Order Book or Liquidity Pool: The Two Designs Compared

The first design replicates an order book of the kind familiar from an exchange: your counterparty is another trader, and the price emerges from supply and demand.

The second design places a liquidity pool between the parties. Whoever commits capital to that pool becomes the counterparty to all open positions and earns fees, but carries the risk of losing against successful traders. For you as a trader that means no spread in the classic sense, and instead fees that follow the utilisation of the pool. Which design each provider uses, and what that implies for cost and risk, is set out in our comparison of perp DEX platforms.

Self-Custody on a Perp DEX: Who Really Holds the Keys

The strongest argument for a perp DEX is that your money remains yours for as long as you do not commit it to a position. No provider can freeze it, and no insolvency drags it along. Given the experience of recent years, that deserves to be taken seriously.

It answers only one of several questions, though. The collateral sits in a smart contract, and that contract is software. Who is allowed to change it, who determines the price source and who can halt trading in an emergency has nothing to do with the custody of your keys. We worked through this distribution of power in early August using two incidents as examples, asking who actually holds the keys at these platforms. At AFX the problem lay, according to our reporting, in the bridge used to move funds between chains, and therefore outside the trading part proper.

In practice: before your first deposit, check whether an admin key exists, who controls it and whether changes to the contract are subject to a time lock. That information is usually in the documentation. If it is missing, that absence is an answer in itself.

MiCA and Perp DEX: Why the Regulation Does Not Apply Here

Many investors assume that since the MiCA transition period ended, everything touching crypto assets is regulated. For derivatives that is wrong. Article 2(4) of the regulation expressly excludes from its scope those crypto assets that qualify as financial instruments. Perpetual contracts are derivatives and therefore fall under the regime for financial instruments, which is MiFID II.

This is no formality. The authorisation a provider can show in the MiCA register says nothing about its derivatives business, and the providers in question here generally hold no EU authorisation at all. You are trading on a venue for which neither a German nor a European supervisor is responsible, with no route of complaint and no investor compensation.

Taxes on Perpetual Futures: Derivative Rules Instead of the Crypto Holding Period

This is where the most common misconception sits, and it costs money. Crypto held privately in Germany falls under the rule for private disposal transactions with its familiar one-year period. A perpetual, however, is not a currency but a derivative transaction. Germany's income tax act covers, in Section 20(2) sentence 1 no. 3, the gain from derivative transactions through which the taxpayer obtains a cash settlement or an amount determined by the value of a variable reference figure.

In practice this means the one-year period does not help you with perpetuals. A gain stays taxable however long the position was open. On the offsetting of losses, subsection (6) in the currently applicable version of the statute no longer contains a separate monetary cap for derivative transactions; a distinct ceiling used to apply here. Whether a specific product qualifies as a derivative transaction in an individual case belongs with a tax adviser and not in a guide. What you can do yourself is keep the underlying data clean: every funding payment, every fee and every liquidation should be documented without gaps.

Who a Perp DEX Actually Makes Sense For

A venue of this kind is worth considering for experienced traders who want to trade without opening an account, who can calculate the cost of a position across its holding period and who can absorb the total loss of the capital they commit. It is unsuitable for long-term wealth building, for anyone who needs a supervisor or a contact person, and for anyone unable to quantify the funding costs.

After this week we regard the question of the price source as the more important selection criterion, ahead of the level of fees. A venue with cheap fees and a vulnerable price feed is the worse place to be.

Note on providers: some providers on our comparison pages are included through affiliate links. This has no influence on the technical details given in this article; they come from the public documentation of the projects and from the statute.

What to Take Away

1. Calculate the holding cost before you open. Take the venue's current funding rate, multiply it by your intended holding period and set the result against the price move you expect. Which platform carries which rates and which fee models is in our perp DEX comparison.
2. Clarify the price source and who holds the keys. Check the documentation for where the mark price comes from, who may change the contract and whether a time lock applies to such changes. If you do not want that framework, trade instead with a supervised provider from our overview of regulated crypto exchanges.
3. Set up your record-keeping before the first trade. Funding payments accrue hourly and add up to hundreds of individual entries a year that are hard to reconstruct later on. A tool that reads the wallet address automatically takes that work off your hands; the common ones are in our comparison of crypto tax tools.

(As of August 7, 2026. This article is not investment advice. Prices and fee structures change; check the terms with the provider before you buy.)