1.   But Wall Street professionals being investigated say the wide spreads can be explained by market practices.

2.   Dealers were keeping trading spreads artificially wide to boost their profits, costing investors millions of dollars, SEC investigators found.

3.   Institutions say traders have grown fat from the wide spreads between the prices at which they are willing to buy and sell securities.

4.   Large Nasdaq dealers are under Justice Department investigation to determine if they colluded to keep trading spreads unusually wide.

5.   One practice in the Nasdaq market that was evidently known to traders, but not to the public, concerned just how wide spreads should be.

6.   One practice in the Nasdaq market that was evidently well known to all traders, but not to the public, concerned just how wide spreads should be.

7.   Such wide spreads have blunted the effect of monetary policy.

8.   The AMEX letter said Nasdaq dealers draw profit from the wide spreads between the buying and selling prices, giving them a possible incentive to maintain the status quo.

9.   The Justice Department is also investigating whether dealers on Nasdaq colluded to keep trading spreads unusually wide.

10.   The investigation is said to focus on unusually wide spreads between bid and ask prices in Nasdaq trading, which the lawsuits attribute to collusion.