Last Modified: September 21, 2017


Gemini operates three distinct order matching engines, one for each of our trading pairs — BTC/USD, ETH/USD, and ETH/BTC. You may submit orders to any of the three matching engines at any time. Our marketplace operates 24 hours a day, seven days a week, except for brief maintenance periods, which we announce ahead of time at @geminidotcom.

You may submit as many orders as they like and of any type described below. Gemini is a full reserve exchange — funds must be deposited prior to placing any order and all orders must be pre-funded (i.e., you are not permitted to place an order unless you have enough funds in your account to place such order). As a result, your outstanding interest on our orders books cannot exceed your account balance at any time and all open orders reduce your available balance until such orders are fulfilled or canceled.

We currently offer two BTC/USD auctions per day, one at 4:00 p.m. Eastern Time (20:00 UTC during EDT or 21:00 UTC during EST) and another at 7:00 p.m. Singapore Time and Hong Kong Time (20:00 JST, 11:00 UTC), and one ETH/USD auction per day at 4:00 pm. Eastern Time (20:00 UTC during EDT or 21:00 UTC during EST).


Order Types

Each matching engine currently supports six order types, as described below.

Continuous Trading Order Types
  • Market — filled immediately against resting orders.
  • Limit — filled at or better than a specified price. Any quantity of a limit order that is not filled rests on the continuous trading order book until it is filled or canceled.
  • Immediate-or-Cancel (IOC) — filled immediately at or better than a specified price. Any quantity of an IOC order that is not is filled immediately is canceled and does not rest on the continuous trading order book.
  • Maker-or-Cancel (MOC) — rests on the continuous trading order book at a specified price. If any quantity of an MOC order can be filled immediately, the entire MOC order is canceled.


Auction Orders Types
      • Auction-Only (AO) Market — filled at the conclusion of an auction at its final auction price.
      • Auction-Only (AO) Limit — filled at the conclusion of an auction at or better than a specified price.


Specifies Price Trades Against Resting Orders Can Rest on Continuous Trading Order Book Can Trade in Auction
Market Yes
Limit Yes Yes Yes Yes
Immediate-or-Cancel (IOC) Yes Yes
Maker-or-Cancel (MOC) Yes Yes Yes
Auction-Only (AO) Market Yes
Auction-Only (AO) Limit Yes Yes
Continuous Trading Order Books

For each trading pair, we offer a continuous trading order book. This allows for continual interactions between market orders and limit orders. Limit orders interacting with an order book may additionally carry one of two options (see below).

If you wish to trade immediately, you may enter market orders to buy or sell. Because these orders do not specify a price constraint, they may be fulfilled at any price or a variety of prices by orders already resting on the order book (see below). For ease of use, market orders to buy must specify a total notional value to convert from one asset to another (e.g., buy $100 worth of bitcoin), from which appropriate trading fees are first deducted. Market orders to sell must specify a total quantity of asset to sell (e.g., sell 5 BTC for USD); appropriate trading fees are deducted from the proceeds. For a more detailed discussion of fees, please see Trading Fees & Rebates.

As with most other marketplaces, you may also place limit orders to buy or sell. These limit orders might not trade immediately, if no other customer is willing to trade at the specified limit price (or better). Any non traded quantity rests on the order book until fulfilled by incoming eligible orders. Thus, a limit order might not immediately be fulfilled; trades depend on interactions with other marketplace participants. You may attempt to cancel your orders while they rest on the order book. The limit price and quantity are specified separately from fees. (Gemini does not currently allow limit orders to be “replaced” or “amended;” you must enter an entirely new order to specify a different limit price or quantity.)

Our marketplace also allows limit orders to be entered with one of two order options: immediate-or-cancel (IOC) or maker-or-cancel (MOC). IOC orders are common on other marketplaces. This option specifies that a limit order should not be allowed to rest on an order book; instead, any quantity not executed immediately is canceled. MOC specifies the opposite: if a limit order would trade immediately against an eligible resting order, it is instead canceled. MOC orders only trade after first resting on an order book. In summary, all trades from IOC orders are liquidity-taking, and all trades from MOC orders are liquidity-making.

Priority of Continuous Orders

Limit orders resting on an order book are filled by price-time priority. That is, if an incoming market or limit order could be fulfilled by multiple resting limit orders, eligible orders at the most favorable price are considered first (i.e., lowest resting sell orders for an incoming buy or highest resting buy orders for an incoming sell). If multiple limit orders are resting at the same price, those which were placed earlier are considered before those which were placed more recently. Partially filled resting limit orders keep their priority until canceled.


In addition to running a continuous trading order book, the BTC/USD matching engine conducts two auctions (or “crosses”) every day, one at 4:00 p.m. Eastern Time (20:00 UTC during EDT or 21:00 UTC during EST) and one at 7:00 p.m. Singapore Time and Hong Kong Time (20:00 JST, 11:00 UTC). The ETH/USD matching engine conducts one auction every day at 4:00 p.m. Eastern Time (20:00 UTC during EDT or 21:00 UTC during EST), in addition to running a continuous trading order book. These auctions provide an opportunity for both buyers and sellers to trade in an instant of elevated liquidity and price discovery. All open orders (including resting limit and MOC orders) may interact with an auction conducted by their matching engine and be considered in establishing the final auction price, which is determined by finding the price at which the greatest aggregate buy demand and sell demand from all eligible orders can be fulfilled (sometimes called a Walrasian equilibrium). All participating, eligible orders are fulfilled at the final auction price. We use an auction mechanism similar to that used by NYSE Arca, Nasdaq, Bats, and other large stock exchanges throughout Europe and Asia.

ET Auction SGT/HKT Auction
AO Orders Accepted 8:00 a.m. 12:00 13:00 11:00 a.m. 12:00 03:00
Indicative Prices 3:50 p.m. 19:50 20:50 6:50 p.m. 19:50 10:50
AO Orders Locked In 3:59 p.m. 19:59 20:59 6:59 p.m. 19:59 10:59
Auction 4:00 p.m. 20:00 21:00 7:00 p.m. 20:00 11:00

You may enter both market orders and limit orders as auction-only (AO) orders, which means they will not take part in continuous trading, but instead only become eligible to trade at the time of an auction. You may submit as many auction-only orders as you want for a particular auction, provided all of your orders are pre-funded. If all eligible orders cannot be fulfilled during the auction (which can occur when demand on one side of the market outweighs demand on the other), eligible orders will be given priority based on time of receipt. If your AO limit order cannot be satisfied by the final auction price, it will be canceled back to you after the completion of the auction. Each auction begins accepting auction-only orders ten hours before its auction time. AO orders may be canceled up until one minute before their auction runs; after that time, they’re locked into their auction.

The final auction price of each auction is determined by finding the price at which the greatest aggregate buy demand and sell demand from all eligible orders can be fulfilled; all continuous trading orders and AO orders are considered. In the event of a tie between multiple prices, the midrange is used. Beginning ten minutes before an auction, indications of its upcoming auction price are broadcast via both our market data API (see ‘Market Data’ below) and our website UI. In order to calculate indications, we simulate the auction process at that point in time. Indicative auction prices are updated every 60 seconds leading into an auction, and every 15 seconds during the final minute. In general, indications should converge on the final auction price and should also provide guidance for prices on the related continuous trading order book.1 If a matching engine does not converge on an effective2 final auction price, the auction will be canceled, all auction-only orders will be canceled back, and all continuous trading orders will be unaffected.

Check out our Auction Data page to see the results of Gemini’s previous auctions.

Priority of Auction Orders

Fills resulting from the auction are allocated solely based on time priority, and it is possible that some orders may receive partial fills or no fills based on the buy-sell imbalance at the final auction price.


Market Data

All trades as well as the summed quantity of limit orders (only standard and maker-or-cancel) resting at each price level throughout our order books on our marketplace are reported to the public via our market data API. Additionally, the value of each digital asset is determined by the most recent trade (sometimes called “last price”) executed by the relevant matching engine; this convention is called “marking to market.” All account balances on Gemini are marked to market.


Market Data Committee

We maintain an internal Market Data Committee that is accountable for the overall operation of our marketplace, matching engines, and market data. This committee is comprised of our CEO, President, Chief Operating Officer, and Chief Compliance Officer.


Periodic Review

We review the codebase, documentation, trading activity, and auction process of our matching engines as part of our periodic review, which is performed in accordance with Principle 10 of the IOSCO Benchmark Principles.3


Marketplace Conduct Rules

We have Marketplace Conduct Rules designed to prevent the use of Gemini for manipulative conduct or deceptive practices, including, but not limited to, price manipulation. We take our Marketplace Conduct Rules very seriously and it is our policy to take all necessary steps to prohibit manipulative conduct or deceptive practices.


Marketplace Controls

In an effort to foster an orderly market and prevent market disruptions, we have the following marketplace controls in place:

  • Automatic cancellation of any order, or the remaining portion of any order, on a continuous trading order book that would move the market price by more than 20% in either direction, as compared to the prior prevailing market price;
  • A confirmation dialogue box that warns you before placing any order on a continuous trading order book that could potentially move the market price by more than 20% in either direction, as compared to the prior prevailing market price;
  • Automatic cancellation of an auction if the final auction price deviates from the midpoint of the related continuous trading order book by more than 5% in either direction at the time of the auction; and
  • Self-trade prevention that prohibits you from crossing with yourself on a continuous trading order book or during an auction.


Trade Errors

Errors or disruptions may occur on our exchange in the order entry, order matching, or trading process. Examples of such errors or disruptions may include, but are not limited to:

  • Data corruption in the authentication process for order entry or order matching that results in an incorrect buy or sell order;
  • A system failure that results in the incorrect population of an order book or incorrect application of a matching engine;
  • Any disruption or malfunction in the operation of any electronic communications, trading facilities, storage facilities, recording mechanisms, or other components of or integral to Gemini or a digital asset network (e.g., the Bitcoin Network); or
  • An order or trade that is empirically disruptive to an orderly market and, therefore, represents a false and misleading view of the market.

We reserve the right to cancel any order and/or reverse any trade, in whole or in part, in the event of a error or disruption pursuant to our User Agreement (seeErroneous Order Policy’ and ‘Erroneous Trade Policy’).

If any such disruptions or malfunctions occur, our Market Data Committee will review any orders and trades from such period and may declare them null and void. Absent extraordinary circumstances, any such action taken by the Market Data Committee pursuant to our User Agreement will be taken within three (3) business days of the detection of any erroneous order, erroneous trade, disruption, or malfunction. We will notify you if you are involved as soon as practicable.


Financial Indices: Compliance Statement

In connection with our auction process, we may publish price indices that reference or incorporate data from auction results. We are the administrator of the resulting indices, and we undertake this responsibility pursuant to and in compliance with the Principles for Financial Benchmarks published by the Board of the International Organization of Securities Commissions (the IOSCO Benchmark Principles). We have implemented the IOSCO Benchmark Principles in a manner proportionate to the size of, and risks posed by, each index that we administer. Specifically, we have implemented and maintain a Market Data Integrity Policy and accompanying procedures that provide an internal control framework governing the creation and administration of financial indices, addressing conflicts of interest, and ensuring data integrity, among other items.


Questions, Feedback, and Complaints

If you have any questions, would like to provide feedback, or would like more information about Gemini, please feel free to contact our Customer Support Team.

If you would like to report a trading error or lodge a complaint,4 please contact our Customer Support Team using one of the following methods:

      1. Complete this form;
      2. Write to our Customer Support Team at:
        Gemini Trust Company, LLC, 600 Third Avenue, 2nd Floor, New York, NY 10016; or
        Call our Customer Support Team at +1 (866) 240-5113 (toll-free in the USA).


Gemini makes no guarantee that indicative prices and final auction prices will converge throughout the process nor that the related continuous trading order book prices will converge. Indicative auction prices, final auction prices, and continuous trading order book prices are solely a product of the interactions of market participants who have no affiliation with Gemini Trust Company, LLC., and our marketplace policies and procedures and rules of conduct.
2 An auction will be automatically cancelled if the final auction price deviates from the midpoint of the related continuous trading order book by more than 5% at the time of the auction.
3 See
4 All trading error reports or complaints must contain sufficient information to facilitate review.