Trading Sessions

CoinJar Exchange runs 3 discrete trading sessions every UTC day. During each trading session, the market sequentially enters into each of continuous, auction, auction_nocancel, and closing states.

All times referenced are in UTC.

Definitions

• Continuous: Continuous orders (GTC/IOC/MOC) are matched on a price-time priority basis. Auction orders (AO) are accepted but not processed.
• Auction: Continuous orders are matched as normal. Auction data is regularly disseminated by the exchange.
• Auction No Cancel: Continuous orders are matched as normal. Auction orders are accepted but cannot be cancelled.
• Closing: Gap time in between sessions. Orders are not accepted or matched.
• Trading Halt: Orders are not accepted or matched.

Auctions

Orders submitted with an AO time-in-force setting participate in auctions, along with any unfilled native orders on the central limit order book at the end of auctions. Auctions take place concurrently with continuous trading. All auction orders are 'dark' and only the following information is regularly published to the market:

• Indicative price: The single price all matched orders would receive if auction ends immediately.
• Auction volume: The volume matched if auction ends immediately.
• Imbalance: A buy imbalance indicates that there will be surplus bids resting at the indicative price if the auction concludes immediately. A sell imbalance indicates that there will be surplus asks resting at the indicative price if the auction concludes immediately.

The best bid must be greater than or equal to the best ask to result in any match, and all matched orders are filled at the final auction price, resulting in price improvement for most orders. The final auction price is determined using the following order:

1. The single price that maximises the volume matched using the merged order book (unfilled continuous orders and all auction orders)
2. If there are multiple prices that satisfy the above, the "minimum surplus" principle is applied to select potential auction prices, i.e. the auction must result in the least total outstanding size in the order book.
3. If imbalance is to the buy side (i.e. there are unmatched buy orders at any potential auction price), the final auction price is the highest potential auction price. If imbalance is to the sell side (i.e. there are unmatched sell orders at any potential auction price), the final auction price is the lowest potential auction price.
4. If there is no imbalance at any potential auction price, the final auction price is the median of all potential auction prices.

Where a surplus exists at the final auction price, orders are matched on a price-auction-time priority basis (AO orders receive priority at the same price during auctions). Final auction prices may not be in whole multiples of a tick. Implied orders are not considered for auctions.

AO time-in-force setting expires after the first auction with a non-zero trade volume. If the auction ends and the order is unfilled or partially filled, the remainder is converted into a GTC order.

Due to the non-continuous nature of auctions, it is important to be aware that the indicative price has the potential to deviate significantly from the market prices immediately before or after the auction. While indicative prices are announced throughout the auction period, they are only indicative of the state of the auction order book at any given time and they may change quickly and significantly when large orders are placed or cancelled.

CoinJar Exchange guarantees that all orders that receive a fill during the auction are filled at the same fill price regardless of limit order prices, and that this fill price is not worse than the limit order price of each order.