Some IPOs contain Green Shoe provisions, named after one of the first firms to include the provision in its underwriting agreement. A Green Shoe provision gives the leading investment bank the right to increase the number of shares sold in the IPO, typically by 10 percent to 20 percent of the original offering. This helps the investment bank satisfy more investors if demand for an issue is particularly hot. This also gives investment banks another way to increase their profits, since they earn the spread on any extra shares they sell.