Kristina Cooke, Pedro da Costa and Emily Flitte:

NEW YORK/WASHINGTON (Reuters) – To the outside world, the Federal Reserve is an impenetrable fortress. But former employees and big investors are privy to some of its secrets — and that access can be lucrative.

On August 19, just nine days after the U.S. central bank surprised financial markets by deciding to buy more bonds to support a flagging economy, former Fed governor Larry Meyer sent a note to clients of his consulting firm with a breakdown of the policy-setting meeting.

The minutes from that same gathering of the powerful Federal Open Market Committee, or FOMC, are made available to the public — but only after a three-week lag. So Meyer’s clients were provided with a glimpse into what the Fed was thinking well ahead of other investors.

His note cited the views of “most members” and “many members” as he detailed increasingly sharp divisions among the officials who determine the nation’s monetary policy.

The inside scoop, which explained how rising mortgage prepayments had prompted renewed central bank action, was simply too detailed to have come from anywhere but the Fed.