A "piggyback" registration rights clause entitles investors to offer their shares in the company to buyers if an offering has already been initiated by the company or another investor. In this manner, some of the shares sold in an IPO or secondary offering will be shares owned by existing shareholders rather than completely comprised of newly issued shares. Such clauses often include "cutbacks" or limitations on the right (e.g. existing investors piggyback offering may be cut back to zero if there is insufficient market demand).