FEDERAL authorities are seeking to build insider trading cases against roughly 120 individuals on and off Wall Street in an expanding criminal insider trading investigation that has shaken the financial and corporate worlds.

The disclosure - the first time authorities have quantified the number of people under scrutiny - comes on the heels of a string of successful prosecutions of insider trading.

Since late 2009, prosecutors have charged 66 individuals at hedge funds and other companies with insider trading and won 57 convictions or guilty pleas.

"We've identified them, and now of course we have to build a case around that," David Chaves, a senior FBI agent, said Monday in an interview following a presentation to reporters at FBI headquarters in Manhattan.

During the presentation, just blocks from Wall Street, the FBI unveiled a one-minute public service announcement against insider trading featuring actor Michael Douglas, whose fictional character Gordon Gekko in the 1987 movie "Wall Street" popularized the line: "Greed, for lack of a better word, is good."

The government currently is investigating whether roughly 240 individuals, including hedge-fund traders and company insiders, improperly shared insider information, said Chaves.

Roughly half of those, or 120, are "targets," meaning the government believes they have violated insider-trading laws and is actively building cases against them, according to Chaves, who oversees one of two white-collar crime squads handling the New York-based insider trading investigations.

The rest are what the FBI calls "subjects," meaning investigators believe they could have committed crimes and have approached them or could do so to build cases.

The large number of "targets" of the investigation - dubbed "Perfect Hedge" by FBI agents - illustrates that the insider trading probe is broader and deeper than previously believed and potentially the most expansive of its kind in modern history.

In the major 1980s insider trading cases, "generally the number of people in a particular ring, you could count on both hands," said Barry Goldsmith, a lawyer who back then was a chief litigation counsel in the SEC's enforcement division.

The current rings are much broader, involving bankers, analysts, corporate insiders, consultants and traders, he said.

Monday's disclosure indicates that arrests could move into new firms on Wall Street and US corporations, and could continue for several more years.

In the past year, the government has won a number of insider trading convictions, using wiretaps and other investigative methods once confined to terrorist and drug cases.

Originally published as FBI probes insider trading cases