The New York Stock Exchange (NYSE) made a filing with the Securities and Exchange Commission to adopt a policy of attaching Aberrant Report Indicators to trade reports that the NYSE determines to be inconsistent with the prevailing market. The Consolidated Tape Association (CTA) offers participant exchanges, including the NYSE, discretion to append such indicators to trade reports. The purpose of the policy is to discourage vendors and other data recipients from using prices to which the NYSE has appended the Aberrant Report Indicator in any calculation of the high, low or last sale price of a security.

In the filing, the NYSE explained that it will retroactively append an Aberrant Report Indicator to trades that do not accurately reflect the prevailing market for a security when it was traded commencing as of January 1, 2007. Trades that are marked by the Aberrant Report Indicator are still valid trades, i.e., they were executed and not unwound as in the case of a clearly erroneous trade. The NYSE’s filing included general numerical guidelines that will be consulted when determining whether trade prices are inconsistent with the prevailing market.

http://www.sec.gov/rules/sro/nyse/2008/34-58736.pdf