At a price: If the stock trades at a certain price or price range, the trader will show this market to the salesperson and thus allow participation under these favorable circumstances.
Floor protection: Representation of a client on the floor of the exchange-so that if size were to trade at his price or a better price, salesperson would participate.
Volume (OTC): If a certain amount of volume trades (that parallels the protectee's interest), trader assures salesperson of reasonable participation in the trading activity. The extent of this protection depends on liquidity, number of market makers, and other aspects of the stock.
Copyright © 2011 Campbell R. Harvey, Professor of Finance, Fuqua School of Business at Duke University