SAC Capital Advisors hedge fund legend Steve Cohen in SEC's firing line

Reclusive Steve Cohen and the Wall Street giant he founded are mired in an inquiry into insider trading that may result in criminal charges

In the high-stakes world of hedge funds, few have been around as long or been as a successful and become as well-known as SAC Capital Advisors, the giant investment business that was founded by Steve "Stevie" Cohen in 1992.

But a dark shadow fell over the $15bn (£9.8bn) firm last week when America's Securities and Exchange Commission (SEC) brought a civil action against Mr Cohen, accusing him of "failing to supervise two senior employees and prevent them from insider trading on his watch".

Now Wall Street is buzzing with speculation that criminal charges against the firm itself could follow as early as this week, with US prosecutors widely reported to be preparing a complaint against the investment behemoth.

Criminal action, if it is forthcoming, would turn a harsh spotlight on and mark a low-point for a business that has been dogged by a series of negative headlines in recent years, as investigators went after a number of former employees accused of insider-trading activity.

Earlier this year, an SAC unit agreed to paid about $600m as part of an insider-trading settlement with the SEC. It did so without admitting or denying any allegations.

At the head of the business is Mr Cohen, a hedge fund veteran known for his trading track record. He founded SAC with just $26m in capital. His exploits during the tech-boom have become Wall Street legend: he was among the few traders who profited both from the boom and the subsequent bust, turning negative before the bubble popped.

A Businessweek cover story in July 2003 anointed him "The Most Powerful Trader on Wall Street You've Never Heard Of". The piece gushed that though Mr Cohen managed less money than "George Soros or Julian Robertson [pioneers of the hedge fund industry] did at the height of their powers … his sheer trading prowess leaves them in the dust".

This fabled prowess made SAC increasingly powerful and Mr Cohen spectacularly rich. As of March this year, Forbes magazine put his net worth at more than $9bn. Though known to be reclusive, Mr Cohen made regular appearances in the press, if not because of the success of his firm, then in his alternative avatar as a deep-pocketed art collector. His collection is reportedly worth about $1bn, and includes works by Picasso, Francis Bacon and Jeff Koons. But more recently, attention has turned to the SAC-linked individuals who have found themselves in the cross-hairs of prosecutors. At least eight current or former SAC employees have faced allegations of insider trading.

A prominent case emerged last year, when authorities arrested Mathew Martoma, a former SAC portfolio manager. He was accused of trading shares in two pharmaceutical companies after getting his hands on inside details about drug trials. The case attracted attention because of the prosecution's allegation that Mr Martoma recommended trades to his "hedge fund owner," an individual identified in a number of reports as Mr Cohen.

The founder of SAC and the firm were not implicated in the complaint, which followed an investigation lasting several years into the hedge fund industry by the FBI, labelled "Operation Perfect Hedge".

Then there was the case of Michael Steinberg, a senior SAC portfolio manager who was arrested in March over allegations of illegal trading in shares of the computer giant Dell and Nvidia, the graphics technology specialist.

Headlines are one thing – but a criminal charge against SEC could be disastrous for the business. Big clients are likely to be wary of investing with a firm that has such a cloud hanging over its activities.

Last night, both the US Attorney's office for the Southern District of New York and a spokesman for SAC declined to comment on the possibility of criminal action.

Friends: The SAC connection

Jon Horvath - Hedge fund analyst

The former analyst at SAC's Sigma Capital unit pleaded guilty to insider trading charges in September, admitting he received illegal stock tips about the PC maker Dell and the graphics company Nvidia ahead of their earnings. He was arrested at the start of 2012 with seven others as part of a "corrupt circle of friends". His sentencing has been delayed until the autumn as he co-operates with prosecutors.

Anthony Chiasson - Founder, Level Global

The co-founder of the Level Global hedge fund became the 70th person convicted in the latest putsch against insider dealers on Wall Street. He was found guilty of making illegal profits of $68m from trading in Dell and Nvidia. The 39-year-old member of the "circle of friends" was sentenced to six and half years in jail. Chiasson founded Level Global with another former SAC trader, David Ganek, in 2003.

Todd Newman - Hedge fund manager

A portfolio manager at the now defunct hedge fund Diamondback Capital, Newman was the 71st person convicted, receiving a 54-month sentence after he was found guilty alongside Chiasson last December in connection with trades in Dell and Nvidia. Diamondback was accused by prosecutors of making about $3m profit from what was described as the largest negative bet ever made by the firm.

Mathew Martoma - Hedge fund manager

The long-time senior portfolio manager at SAC's Sigma unit, where he was Jon Horvath's boss, was arrested in March. He was accused of illegal trading in Dell and Nvidia based on "insider information that Horvath obtained from a circle of research analysts at several different investment firms". Mr Steinberg has pleaded not guilty and his case is due to go to trial in November.

Michael Steinberg - Hedge fund manager

Another former SAC portfolio manager, Martoma was arrested amid a blaze of publicity in November last year. Authorities accused him of trading in shares of the pharmaceuticals companies Wyeth and Elan based on insider information about trials. Mr Martoma has denied any wrongdoing and his trial is set to begin in November.