Because of recent surges in electronic trading volume, we are making an important change in how trade ID's are assigned.  This change will provide more flexibility and expand the range of available trade ID numbers.  This advisory describes this change, and related points regarding the usage of firm trade ID's. 

Beginning Monday September 17, 2007, there will no longer be a distinction between the range from 100,000 to 499,999 and the range from 500,000 and up.  Instead, each day we will begin at 100,000 and assign trade ID's sequentially, for the combined pool of electronic trades, giveup and average-pricing transfers, calendar spreads treated as SLEDS, etc.  This change is being done to provide the greatest possible number of trade ID values below one million.  Firms should note, however, that trade ID's for electronic trades will no longer be guaranteed to be sequential.

  For the full text of this advisory . . .