We know that one of the principal focuses of the government in their investigation into insider trading in general—and into hedge funds in particular—are the so-called "expert-network" firms.

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The purpose of the expert network firms is to provide information and insight about companies that investors are interested in—and also, perhaps more crucially, to help manage the relationships between the investors and the managers of companies they seek to invest in. Think about the nature of that scenario: Investors and managers chatting together informally, outside the scope of more traditional venues like earnings calls and IR events. It seems a safe bet that, amid allegations of widespread insider trading, the government might be interested in exploring that channel to see if material nonpublic information might have changed hands.

Today, the news is that Gerson Lehrman Group, the largest of the expert network firms, had at least one of its consultants questioned by the FBI. For those not familiar with the hedge fund/expert network axis, the significance of this may not be immediately obvious.

While Gerson Lehrman Group may sound to the uninitiated a bit like a dish prepared by the Swedish Chef on the Muppets, this firm is a very serious player in the expert network space. The Wall Street Journal reports that "Gerson controls two-thirds of the market for expert networks"

To put that number in perspective, think about this: JPMorgan is the current leader in capital markets transaction—and they control only 7.8 percent market share.

So, in the space they play in, Gerson is a vampire squid on steroids.

The Wall Street Journal article alludes to the significance: "The FBI questioning of the Gerson consultant shows the government's examination of the expert-network business is broader than Primary Global. Criminal and civil authorities are investigating whether these consultants passed inside information to clients, who pay the expert companies large fees for their services."

It seems that it's not just Gerson in the crosshairs—but more broadly the clients they serviced.

And which firms are Gerson clients?

According to the Journal: "In recent years, Gerson's client roster has included prominent hedge funds like SAC Capital Advisors LLC, mutual-fund company Fidelity Investments, private-equity firm Carlyle Group LLC and Wall Street investment banks, said people familiar with the matter."

The phrase "has included" tells you that we're not looking at an exhaustive inventory in the list that follows—but only a sampling.

And the message from that sample seems to be that Gerson clients are many of the big boys.

Interestingly, no "Wall Street investment banks" are cited by name – but if the sampling of hedge funds and private equity groups provided is representative of the caliber of firms Gerson did business with on the banking side, you might expect to see some of your favorite A-list players from the top of the banking league tables represented on their client list.

The Journal article reports that Diamondback Capital —which has already been raided by the FBI in the probe—is a client of Gerson.

It is important to note that no allegations of wrongdoing have been made against Gerson or any of its employees related to the current probe.

Nonetheless, one's curiosity might naturally be piqued by the client list and the nature of the relationships involved—enough to keep following this story. Closely.

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