Remember that agencies like the IRS, FDA, SEC must not leak a single bit of information (investigation/no investigation). Because that single bit is sufficient to profitably trade on. A hedge fund doesn't need to know the specifics or the exact date of an enforcement announcement in order to make out like a bandit. A tiny amount of signal is sufficient. In fact, a tiny amount of signal is preferred. If a firm knows for a fact that MSFT is in trouble with the IRS they can't trade on it. But if a little bit of information leaks from an agency, that's gold.
