http://www.isld.com
2. Instinet
http://www.instinet.com
3. Optimark
http://www.optimark.com
4. Archipelago
http://www.tradearca.com
5. REDIBook
http://www.redi.com
6. ITG
http://www.itginc.com
7. ASB
http://www.taltrade.com
8. Brass / Brut
http://www.sungard.com
9. Strike Technologies
http://www.striketech.com
10. Attain
http://www.attain.com