The Prop Trader's Chronicles: Short-Term Proprietary Trading Strategies for Both Bull and Bear Markets

ISLAND-NASDAQ MAIN ECN (“Q”)

Island is currently a historical component of the letter Q on most stocks (NASDAQ ECN). For the purposes of memorization, let's call them Q for being quick to the market in a number of ways. The current incarnation of Island is actually NASDAQ's main ECN platform, but the ECN that NASDAQ bought out in 2005 was actually the product of a merger between the original Island ECN and the Instinet ECN in 2002 to become INET. NASDAQ itself was the world's first electronic stock market, launched in 1971. It was in many ways the Island that started it all when it comes to purely electronic order matching systems on modern stock markets.

Memorization key: Island, Instinet, and NASDAQ combined to become today's incarnation of NASDAQ's main ECN, which is Q for being quick to the ECN market.

So when you see “12:02:59 12.50 100 Q” on a stock's tape in a typical prop firm's trading platform, it means a transaction took place at 12:02:59 at the price of 12.50 for 100 shares, and this transaction was matched on Q, the NASDAQ ECN. (There's another reason to continue to think of this ECN as Island. As of this writing, its parent company, NASDAQ OMX Group, owns a number of other ECN platforms including the former Boston and Philadelphia exchanges, which have separate letter designations and very different pricing schemes and features, and are now known as NASDAQ OMX BX and NASDAQ OMX PSX, each with unique advantages and disadvantages in their offered order types. So it's ...