LaBranche CEO Resigns From NYSE Board

The battle lines between the New York Stock Exchange and LaBranche & Co., the exchange’s largest specialist firm, deepened Thursday as LaBranche’s chief executive resigned as New York Stock Exchange vice chairman and director.

LaBranche has been locked in a fight with the NYSE as the firm refuses to hand over certain e-mails as part of a Big Board investigation.

The exchange is reviewing the trades of some of its specialists -- traders on the NYSE floor who manage the buying and selling of shares -- for possible violations of the obligation to stand out of the way if a buyer and seller are available to trade without “undue” dealer intervention.

The NYSE in a brief statement said LaBranche CEO Robert Murphy had resigned from its board, effective immediately.

Murphy could not be reached for comment.

Murphy was one of four directors on the 27-member NYSE board who represent floor traders.

LaBranche, one of the firms being investigated, said that its employees have provided the NYSE numerous interviews and that the firm has turned over thousands of e-mails. But it drew the line at turning over e-mails it said were personal and not relevant to the investigation.

LaBranche’s stock fell 24 cents to $16.83 in NYSE trading.