Why a large market order is rejected: market order size limits by exchange

A market order takes liquidity from the order book at once. Exchanges limit how much one order can take. The limit is set per instrument and can change when the exchange updates risk parameters. If your close is larger than the cap, the exchange rejects it. Closing a large position is where traders hit this most often.

What is the market order limit on each exchange?

Exchange	Where the limit lives	Unit	Rejection
OKX	maxMktSz in instrument data	Contracts for futures and swaps. USDT amount for spot and margin	51202 “Market order amount exceeds the maximum amount.”
Binance	MARKET_LOT_SIZE filter, field maxQty	Base quantity	-4005 QTY_GREATER_THAN_MAX_QTY
Bybit	lotSizeFilter.maxMktOrderQty (linear and inverse), maxMarketOrderQty (spot)	Base quantity	Order rejected
Hyperliquid	Contract specifications	Order value in USD, based on max leverage	Order rejected

OKX

The instruments endpoint returns maxMktSz. For a derivatives contract the value is a number of contracts. For SPOT and MARGIN it is a quantity in USDT, which is easy to misread as base coin. OKX also publishes maxMktAmt, a maximum USD amount for a single market order on spot and margin. Error 51201 (“The value of a market order can’t exceed {param0}”) is the related value check.

Binance

Binance has two quantity filters. LOT_SIZE applies to limit orders and MARKET_LOT_SIZE applies only to MARKET orders. Each has minQty, maxQty and stepSize. The two maxQty values can differ, so an order that works as a limit order can still fail as a market order. Read both from exchangeInfo for the symbol.

Bybit

For linear and inverse contracts, lotSizeFilter.maxMktOrderQty is the maximum quantity for a market order, and maxOrderQty is the limit and post-only maximum. Spot uses maxMarketOrderQty and maxLimitOrderQty. The Bybit create-order documentation adds one useful rule: if reduceOnly=true and the quantity is above the maximum order quantity, the order is split into several orders automatically.

Hyperliquid

Hyperliquid caps the value of a market order by the asset’s maximum leverage:

Max leverage	Max market order value
25x or more	$30,000,000
20x up to 25x	$5,000,000
10x up to 20x	$2,000,000
Below 10x	$500,000

The maximum limit order value is 10 times the market order value for the same tier.

How do I get a large order through?

1. Read the market cap for the instrument (maxMktSz, MARKET_LOT_SIZE, maxMktOrderQty, or the Hyperliquid tier).
2. Split the total into parts at or below the cap, rounded to the instrument’s step size.
3. Send the parts together when the exchange has a batch endpoint. Binance POST /fapi/v1/batchOrders takes up to 5 orders per request and processes them concurrently, so the fill order is not guaranteed.
4. Keep reduceOnly on closing orders so a rounding error cannot open a position in the other direction.
5. Check the result of every part. A batch can partly succeed.

Limit orders have their own caps (maxLmtSz on OKX, LOT_SIZE on Binance, ten times the market value on Hyperliquid), so working a position out with limit orders is another route.

How Ninja Terminal handles this

Ninja Terminal plans the split before it sends the order, so the exchange never sees an order it must reject:

• Binance USD-M: a market order above MARKET_LOT_SIZE goes out as one batch of smaller orders.
• OKX swaps: a market order above maxMktSz goes out as several orders.
• Hyperliquid: Ninja Terminal sizes each part under the value cap for the asset and sends all parts in one signed action.
• Bybit: closing orders always carry reduceOnly, so Bybit splits them itself.

Large orders still move the price. Review slippage risk and depth before you send size. This guide is not investment advice.