Occurs when an order arrives and interest is already resident in system
Concludes immediately
For market orders and executable limit orders
Step 1 Before an auction occurs, participants anonymously enter their bidding interest using PRIs. Every PRI contains an absolute share size and a price that is relative to the NBBO.
The system ranks PRIs on relative price and time of entry. In this example the best "buy" PRI is for 2,500 shares at Bid +.04. The next best PRI is 1,000 at +.03, and so on.
Step 2 A broker/dealer forwards an order to The Primex Auction, which receives it and conducts an auction based on the interest that is already resident.
The PRI at +.04 automatically responds and wins the auction.
Step 3 The order interacts with the PRI at +.04. The execution price is 20.04, or 4 cents better than the Best Bid at the time. The PRI declines in size by 1,500 shares.
Step 4 The auction takes an instant to complete. The trade is forwarded to Nasdaq.
