The ARCA ECN is available for NASDAQ trading from 8:00 AM EST to 8:00 PM EST (9:30 AM EST to 5:00 PM EST for Listed securities).
When Ultimate Trader routes orders to ARCA:
ARCA will NOT accept Market orders from 4:00 PM ET to 9:30 AM ET.
You can post using the same guidelines as you would using Instinet, meaning you can also lock or cross the market. (See the description below.)
You can also preference on ARCA, but unlike SelectNet you are setting a preference for a specific price as opposed to a MM or ECN.
ARCA will scan its internal order book, and if your price is not available ARCA will then scan all MMs and ECNs until your order is filled or killed. If the market moves away from your price, your order may be killed as well.
There is an additional 0.005 cent per share charge on all ARCA orders.
You are prohibited from locking or crossing the market. You cannot offer at the bid or below it nor can you bid at the ask or above it. Locking the market means bidding at the current ask price or offering at the current bid price. Crossing the market means bidding above the current ask price or offering below the current bid price.
ARCA proactively prevents the creation of locked or crossed markets automatically. When ARCA receives an order that will lock or cross the NASDAQ market, ARCA’s quote updating system will now compute the optimal display price to send to NASDAQ which will represent the order to the fullest extent possible within the limitations of NASDAQ’s systems and rules. In all situations, however, ARCA subscribers and non-subscribers will only receive an execution at the order entry price.