Primary Listing Exchange Designation

1. UMIR Requirements

UMIR 1.2(5) sets out the price of a security to be used for the purposes of determining the size of the “standard trading unit” for that security. Specifically, Participants must use the last sale price of the security on the immediately preceding trading day on the exchange on which the security is listed or the QTRS on which the security is quoted in order to determine the particular standard trading unit size for that security.

Where a security is listed on more than one exchange, we refer to the last sale price on the “Primary Listing Exchange” to determine the standard trading unit of that security.

Using the correct price in order to determine the standard trading unit of a security is essential for a Participant to comply with UMIR provisions that involve the concept of a standard trading unit, including:

• Section 6.3 Exposure of Client Orders
• Section 6.6 Provision of Price Improvement by a Dark Order
• Section 8.1 Client-Principal Trading.

2. Designation of Primary Listing Exchange

2.1 First Exchange on Which a Security is Listed

CIRO designates the first exchange on which a particular security is listed to be the Primary Listing Exchange.

2.2 Simultaneous Listings

In the case where a security is listed on multiple exchanges simultaneously, CIRO would designate the exchange with the greatest percentage of overall total trading volume in the previous year as the Primary Listing Exchange for that security.

Should a situation arise that is not addressed above and there is uncertainty regarding the Primary Listing Exchange for a particular security, CIRO would publish a notice citing the designated Primary Listing Exchange for that security to eliminate confusion.

3. Applicable Rules

UMIR Rules this Guidance Note relates to:

• UMIR 1.1
• UMIR 6.3
• UMIR 6.6
• UMIR 8.1

4. Previous Guidance Note

This Guidance Note replaces Guidance Note 21-0139 - Primary Listing Exchange Designation (August 9, 2021).