NASDAQ
The NASDAQ Stock Market lists around 3,000 firms. It has steadily introduced ever-more￾sophisticated trading platforms, which today handle the great majority of its trades.
The current version, called the NASDAQ Market Center, consolidates NASDAQ’s previous
electronic markets into one integrated system. NASDAQ merged in 2007 with OMX,
a Swedish-Finnish company that controls seven Nordic and Baltic stock exchanges, to form
NASDAQ OMX Group. In addition to maintaining the NASDAQ Stock Market, it also main￾tains several stock markets in Europe as well as an options and futures exchange in the U.S.
NASDAQ has three levels of subscribers. The highest, level 3 subscribers, are registered
market makers. These are firms that make a market in securities, maintain inventories of
securities, and post bid and ask prices at which they commit to buy or sell shares. Level 3
subscribers can enter and change bid–ask quotes continually and have the fastest execution of
trades. They profit from the spread between bid and ask prices.
Level 2 subscribers receive all bid and ask quotes but cannot enter their own quotes.
They can see which market makers are offering the best prices. These subscribers tend to
be brokerage firms that execute trades for clients but do not actively deal in stocks for
their own account.
Level 1 subscribers receive only inside quotes (i.e., the best bid and ask prices) but do not
see how many shares are being offered. These subscribers tend to be investors who are
not actively buying or selling but want information on current prices.

概括

纳斯达克证券交易所上市企业约3000家，其持续升级的交易平台已能处理绝大部分交易。当前运行的”纳斯达克市场中心”系统整合了原有电子交易市场，2007年与北欧-波罗的海交易所运营商OMX合并后组建纳斯达克OMX集团，除主市场外还运营多家欧洲交易所及美国衍生品交易所。

该交易所实行三级会员制：最高级的三级会员是注册做市商，持有证券库存并持续报价，通过买卖价差获利且享有最快交易执行速度；二级会员可查看全部报价但无权报价，多为代理客户交易的经纪商；一级会员仅能获取最优买卖报价信息，主要服务于非活跃交易的价格查询需求投资者。