To help meet the "reasonable" criteria regarding size, the SEC proposes a size-discovery IOI that would be allowed and only interact against another large order.

FORBES: Magazine Article

Another item in his portfolio is IOI Corp.

FORBES: Unloved Asia

Other dark pools may show symbol and side, send single or market-wide IOIs or set criteria such as minimum participation requirements so that when an IOI message is distributed either to a single contra-side or a marketplace, there are ways of "reading" into the order information.

FORBES: Don't Be Afraid Of The Dark Pools