what is the maximum greenshoe 
usually the maximum amount of extra shares the underwriters can sell is 15 more than the initial agreed upon amount the bottom linegreenshoe options give underwriters the opportunity to sell more shares during an ipo they help to meet high demand and increase the amount of capital a company raises and are very common in the u s typically the over allotment provision permits underwriters to sell up to 15 more shares at the agreed upon ipo price and can be exercised within 30 days after the ipo 