Arcus order types: limit, stop, take profit, reduce only

Arcus order types at launch are market, limit, stop-market, stop-limit, take-profit, stop-loss and reduce-only. Take-profit and stop-loss trigger on the mark price rather than the last traded price. TWAP, trailing stops and OCO are documented questions whose answers Arcus has not confirmed, so this page says so rather than guessing.

That list is short by the standards of a mature perps venue and complete by the standards of a beta. It covers entering, exiting, protecting a position and closing one without accidentally opening another, which is most of what a directional trader needs. It does not cover execution algorithms or conditional order pairs.

One structural point before the detail: these order types belong mostly to perps, which run on a central limit order book and sit behind an invite code. Spot Stock Tokens trade through an RFQ mechanism where market makers quote and you accept. Arcus is also unavailable in the United States, the United Kingdom and Canada, plus other restricted jurisdictions in the Terms.

The seven documented order types

Order type	What it does
Market	Executes immediately at the best available price, paying the taker fee
Limit	Rests at a price you set and fills only at that price or better
Stop-market	Becomes a market order once the trigger price is reached
Stop-limit	Becomes a limit order once the trigger price is reached
Take-profit	Closes a position at a favourable trigger level, on mark price
Stop-loss	Closes a position at an adverse trigger level, on mark price
Reduce-only	A flag that stops an order from increasing your position

Market and limit are the two primitives. On an order book, a market order crosses the spread and pays the taker fee, which starts at 0.045% at the base tier on Arcus and is halved to 0.0225% during beta. A limit order can rest and earn the maker side, which is zero for tiers 0 to 4 during beta.

Both of those schedules are temporary, described by Arcus as applying for the duration of beta, so a strategy built around free maker fills is a strategy with a known expiry risk. The fee page has every tier, and the calculator does the arithmetic on a specific position.

The stop variants differ only in what they become. A stop-market prioritises getting out: once triggered, it takes whatever the book offers, which in a fast move can be considerably worse than your trigger. A stop-limit prioritises price: once triggered, it rests as a limit order, which can leave you holding a position you intended to close if the market runs past your limit. There is no version of this choice that protects you from both outcomes.

Why mark price triggers matter

Arcus documents take-profit and stop-loss as triggering on the mark price. Mark price is a reference price a venue calculates for margin and liquidation purposes rather than the price of the most recent trade, and the distinction has two practical effects.

A single thin print cannot trip your stop. On venues that trigger on last trade, one aggressive order in an illiquid book can spike through a cluster of stops and then revert, taking people out of positions that would otherwise have survived. Mark price triggering reduces that.

The flip side is that your stop can fire when no trade happened at your level, because the mark moved there. If you are used to reading a chart of executed prices and reasoning about where your stop sits, a mark-price trigger will occasionally look wrong. It is not; it is measuring a different thing. The same mark price drives liquidation, which is covered on the liquidations page, so having stops and liquidations reference the same number is at least internally consistent.

Reduce-only, and why it is more useful than it sounds

Reduce-only is a flag rather than an order type in its own right, and it solves a specific, common and expensive mistake. If you are long and place a sell order larger than your position, a venue without reduce-only will happily close your long and open a short with the remainder. Reduce-only refuses to do that.

It becomes more important the more exit orders you keep in the book at once, and more important again with isolated margin, which Arcus shipped on 9 September 2026 and which lets you ring-fence collateral per position. If you are managing several positions with resting stops and targets, reduce-only is the difference between a tidy exit and an unintended reversal. The perps overview covers cross and isolated margin in more detail.

Spot works differently

None of the above is quite how spot behaves. Arcus explains its design logic as RFQ for Stock Tokens and a central limit order book for perps. Under RFQ, market makers send you a quote, and your decision is to accept it or not. There is no book to rest a limit order in, and the cost is expressed as spread inside the quote rather than as a fee, which is how Arcus can charge 0% on spot Stock Tokens.

The consequence for execution is that the quote is the whole story. Arcus says slippage widens outside US market hours, so a quote at 3am will typically be worse than one during the New York session, even though the market is open around the clock. Comparing the quote to the underlying stock price before accepting is the spot equivalent of choosing an order type carefully. The Stock Tokens page covers what the instrument is, and the setup walkthrough covers placing a first spot trade.

What is not confirmed

Three things come up repeatedly and have no documented answer as of 2 October 2026.

TWAP orders, which slice a large order across time to reduce market impact, are not mentioned on any Arcus page found. Trailing stops, which follow price at a fixed distance, are likewise undocumented. OCO pairs, where filling one order cancels the other, are not documented either, which is notable because a take-profit and a stop-loss on the same position is exactly the case OCO exists to handle. Arcus has not said whether placing both leaves you exposed to a double fill.

Time-in-force options are also unpublished. Good-till-cancelled, immediate-or-cancel and post-only are near-universal on order-book venues, and Arcus documents none of them. The absence of documentation is not evidence that the feature is missing, and it is not evidence that it exists. If one of these is load-bearing for how you trade, the honest advice is to ask Arcus support before committing size, and to treat any third-party guide that states a confident answer with suspicion.

Risks

Order types are risk management tools, not risk removal tools. A stop can slip badly in a gap, a stop-limit can fail to fill at all, and a position can be liquidated faster than any resting order helps. Leverage runs up to 50x depending on the market, and most leveraged traders lose money.

Stock Tokens are issued by Bitstamp Global Ltd and are not shares: no voting rights, no dividend claim as such, no guaranteed redemption for the underlying and a price that can diverge from the real stock. Nothing on this page is financial advice.