COLUMN - The missing pieces in Galleon's puzzle: Matthew Goldstein

-- Matthew Goldstein is a Reuters columnist. The views expressed are his own --

By Matthew Goldstein

NEW YORK (Reuters) - Think of the Galleon Management insider trading case as a puzzle with several pieces left to be snapped into place by federal authorities.

Prosecutors and securities regulators appear to have already put together the big pieces with last month's arrests of former Galleon co-founder Raj Rajaratnam and two executives from a former Bear Stearns hedge fund.

Another round of criminal charges may show just how far the outer boundaries of the Galleon puzzle extend. Federal authorities are trying to determine whether other hedge fund managers traded on the same kind of top-secret corporate information that prosecutors say Rajaratnam and former Bear fund managers Mark Kurland and Danielle Chiesi trafficked in. All three are contesting the charges.

The new charges may come fairly soon, say a number of defense lawyers close to the investigation.

At least five people not named as one of the initial six defendants in the biggest insider trading case in two decades have retained lawyers in the wake of the arrests, these lawyers say.

A lawyer with the Securities and Exchange Commission Wednesday seemed to confirm that development when she told Judge Jed Rakoff that there was a "real possibility" of regulators adding additional defendants to a related civil lawsuit.

So far, federal authorities have portrayed a complex multi-year scheme, contending that Rajaratnam, Kurland and Chiesi traded on corporate secrets about upcoming deals or earnings news. The information, prosecutors say, was passed onto the hedge fund managers by executives at tech heavyweights like Advanced Micro Devices, IBM and Akamai Technologies -- some of whom have also been charged.