Advanced strategies that Warren Buffett's mentor recommended for professional investors.
For professional investors, Benjamin Graham — Warren Buffett's mentor — described various special situations or "workouts".
“There is also a fairly wide group of “special situations,” which over many years could be counted on to bring a nice annual return of 20% or better, with a minimum of overall risk to those who knew their way around in this field. They include intersecurity arbitrages, payouts or workouts in liquidations, protected hedges of certain kinds. The most typical case is a projected merger or acquisition which offers a substantially higher value for certain shares than their price on the date of the announcement.”
But these require more than the average level of ability and experience.
Special situations are discussed in more detail as Strategy #5 of How To Build A Complete Benjamin Graham Portfolio .