With the recent change in Island orders on the QQQ and the Instinet merger this might be an interesting topic. During August the Instinet ECN did 17.8% of all NASDAQ volume and 19.1% of the trades. In comparison, in August Island did 11.6% of all NASDAQ volume and 16.7% of the trades. Although in the past Instinet has been considered an "Institutional" ECN, based on this liquidity you would think more people would discuss using Instinet as their "core" route. However when you look at the published number from most firms you find Island as the dominant route for NASDAQ trades. For example - last month 70% of Cybers orders went to Island and only 10% went to Instinet. This appears to be the general trend for most of the retail firms, (e.g for MB it was 44% Island - 11% Instinet in July). Almost every novice trader I have talked to swears that Island is the only way to go for NASDAQ trading and most think it is the largest ECN. From my understand - the large majority of firms do not own their own Instinet line. When a firm does not own a line their Instinet orders are routed through another firm that does own the line. This both slows the order down and increases the cost. I have a feeling that the major reasons Island dominants in many firms is that they do not own an Instinet line. I know a few firms that own their own Instinet line and their traders swear by INCA's execution speed lately (better fills, fast, etc.) and the price is similar to Island. I would be interested in people opinions on Instinet trading with their current firms (price and speed). Does your firm own an Instinet line? Are there any traders that use INCA as their core route?