MEMX is releasing a new version of the trading platform Monday, May 10, 2021. This release contains the following changes with regard to order handling of resting displayed odd lot orders and resting hidden orders, as described below.
These changes are currently available for testing in our MDE environment.
Resting Displayed Odd Lot Orders – Locked or Crossed by Another Market
- Current behavior – when an away market publishes a protected quotation that locks or crosses the displayed price of an odd Lot order and MEMX does not have a protected quotation displayed at such price, the displayed odd lot order will be:
- re-priced, if the order contains a multiple price sliding instruction; or
- canceled.
- Modified behavior – when an away market publishes a protected quotation that locks or crosses the displayed price of an odd Lot order and MEMX does not have a protected quotation displayed at such price, the displayed odd lot order will be:
- re-priced, if the order contains a multiple price sliding instruction;
- routed, if the order was routable on entry to MEMX; (NEW) or
- canceled.
Note: when the NBB locks or crosses the displayed price of an odd lot offer with a short sale instruction in a security that subject to a short sale circuit breaker, the Exchange will continue to cancel such order, as it does today.
Resting Hidden Orders – Crossed by Another Market
- Current behavior – when an away market publishes a protected quotation that crosses the ranked price of a hidden order resting on the MEMX Book, the hidden order will be canceled.
- Modified behavior – when an away market publishes a protected quotation that crosses the ranked price of a hidden order resting on the MEMX Book, the hidden order will be:
- routed, if the order was routable on entry to MEMX; (NEW) or
- canceled.
Examples
- Resting displayed odd lot locked or crossed by protected quotation:
- NBBO is 10.01 by 10.02
- MEMX has a resting displayed odd lot limit order to buy 10 shares at 10.01 that is eligible to route
- There are no other bids on the MEMX book
- NBBO moves to 10.00 by 10.01
- Result: MEMX displayed odd lot bid at 10.01 will be routed to the exchange that is displaying a 10.01 offer
- Additional Notes:
- If the order was instead subject to multiple price sliding it would be re-priced;
- If the order was neither eligible to route nor subject to multiple price sliding it would be canceled;
- If MEMX also had a bid at 10.01 that was >= 100 shares, the displayed odd lot order would stand its ground and would not be routed, re-priced or canceled.
- Hidden order crossed by protected quotation:
- NBBO is 10.01 by 10.02
- MEMX has a resting hidden limit order to buy at 10.01 that is eligible to route
- NBBO moves to 10.00 by 10.01
- MEMX hidden bid at 10.00 stays at 10.01
- NBBO moves to 9.99 by 10.00
- Result: The hidden MEMX bid will be routed to the exchange with the offer at 10.00. Currently, the Trading Platform would cancel that order.
- Additional Notes:
- If the order was not eligible to route it would be canceled
- The handling is the same for hidden orders of round lot, mixed lot, and odd lot size
Our Market Operations and Member Experience teams are here for any of your questions.
MEMX Market Operations
1-833-415-6677
MEMX Member Experience
1-833-415-6369