Auction Mode is a new mode of the exchange order book similar to the Limit-Only and Post-Only modes that brings price discovery auctions to the exchange. In Auction Mode, customers can submit limit orders but no matches will occur. Only limit orders with the “Allow Taker” flag will be accepted during Auction Mode.
While in this mode, limit orders are collected over a minimum of 10 minutes for price discovery. While orders are placed on the book, the Pro and Exchange applications along with the API and data feeds will show an indicative price — a price that may be used to match orders when the auction is opened. Using this indicative price as a signal of the eventual open price, users can cancel and resubmit orders while the auction takes place.
Upon completion of the auction, orders crossing the final opening price will be matched and the book will move to full trading or limit only.
When does Auction Mode take place?
Auction Mode may be used to launch new order books and to relaunch previously paused books.
How long will the auction last?
A minimum of 10 minutes, or until a stable open price is established for low liquidity books.
What order types are supported during the auction?
Only limit orders are accepted while in Auction Mode. Limit orders marked with “Post-only” are not available during Auction Mode and will be rejected along with market orders
What fees are there if I participate in the auction?
Only limit orders are accepted while in Auction Mode. For orders matched when the market opens, both sides are charged taker fees. Orders that remain on the book during full trading are charged the standard fees (maker or taker).
How does an auction work?
There are three phases to the auction before the order book returns to Full Trading or Limit Only: Collection, Match, and Completion.
This is the longest phase where the indicative price is established. Limit orders (without post-only) can be placed during this phase of the auction. Orders can be canceled and resubmitted during the Collection phase.
Orders that crossed during the Collection phase are now paired off and "matched" as taker orders. During this phase, any type of order can be submitted, but they'll be queued in the trading engines. This phase should take no longer than 15 seconds.
The order book is uncrossed, the indicative price is set as the opening price, and full trading begins. Queued orders from the Match phase enter the order book.
Is Auction Mode supported through the API?
Yes. Orders can be placed through the API using the standard endpoints. Additionally, you can get the indicative open price and size as well as the resulting indicative bid and asks through the REST API and through the websocket feed. For more information about APIs, please see these documents.
What are Crossed Markets?
A crossed market is when a market's "bid" price is higher than the "ask" price. While a book is in Auction Mode, the data feeds may show a crossed market. This is consistent with the goals of the auction as it collects orders to aid in price discovery before continuous trading. After the auction completes, the order book will no longer show a crossed market.
What information is available during Auction Mode?
While in Auction Mode, the Pro and Exchange product pages will make a note about the status of the order book, and show the following new information:
A status message indicating we are in Auction Mode
The Indicative Bid price and size. This is an indication of the best bid price and size following completion of the auction
The Indicative Open price. This is the discovered price
The Indicative Ask price and size. This is an indication of the best ask price and size following completion of the auction
A potentially crossed order book while in Auction mode
Note: Since these indicative quote messages get disseminated on an interval basis, the values aren’t firm as changes in the book may occur between the last update and transition from auction mode and full trading.