LaBranche says it has done nothing wrong and is fully cooperating with the pending investigation.

FORBES: Billion-Dollar Blunders

LaBranche made the comment on a conference call with analysts earlier this week.

FORBES: How Much Is That NYSE In The Window?

But it now means LaBranche is the only company at the centre of the inquiry to be without board representation.

BBC: New York market dispute heightens

LaBranche and the other independent firm, Van Der Moolen Specialists USA (nyse: VDM - news - people ) are unlikely buyers because of market concentration.

FORBES: 's Chief Executive Kenneth Lewis

LaBranche said its employees had handed over numerous interviews and thousands of emails but drew the line at those it claimed were personal and not relevant to the investigation.

BBC: New York market dispute heightens

And LaBranche, a marketmaker on the New York Stock Exchange, is withholding some 8, 000 e-mails from the exchange in a row over how an investigation into trading practices is being conducted.

ECONOMIST: Ebbers’ tangled legacy | The

The largest independent firm, LaBranche (nyse: LAB - news - people ) warned last week that it would miss first-quarter expectations, blaming low volatility and a higher percentage of program trading activity.

FORBES: Magazine Article

Getco is getting the business by way of buying it from Barclays, which had to shed some of its assigned stocks after acquiring the designated market maker business of LaBranche, one of the old-guard specialist firms.

FORBES: Out With the Old, In With the New

Shares of LaBranche dropped 16% Friday.

FORBES: The NYSE Trades Up

Five of the NYSE's seven specialist firms are believed to be under scrutiny, including market leader LaBranche (nyse: LAB - news - people ), which is in a nasty fight to avoid turning over employee e-mail traffic to investigators.

FORBES: Billion-Dollar Blunders