The news rules have allowed ECNs to enter the market. On January 1999, 9
ECNs had been approved by Nasdaq. The combination of the handling and the
quote display rules allow each investor (and no longer only the most important
players) to have access to the best quotes.
The new SEC rules have deeply affected the ECN industry. Prior to the
changes, the presence of an alternative pricing system, by means of ECN, proprietary
trading systems, used by market makers and large institutions, permitted
dealers to quote one set of prices for retail customers on Nasdaq, while offering
more favorable prices to other market-makers or institutions.
Under the new SEC rules, if a dealer places a limit order either as agent or
13
principal into Instinet or another ECN, the price and quantity are incorporated
in the ECN quote displayed on Nasdaq. Under this option, the dealer directly
o¤ers price improvement, but is not required to display quote sizes larger than
their minimum on Nasdaq. One feature of this rule is that SOES is immobilized
when the inside quote is established by an ECN because ECNs are not
required to participate in SOES. Furthermore, ECN quotes, which were on a
…ner quotation grid than Nasdaq quotes, were rounded to the nearest eighth
on Nasdaq. E¤ective June 3, 1997, Nasdaq market moved to quote increments
of one-sixteenth, implying that rounding should take place to the nearest sixteenth.