greenshoe
an option granted by the offeror in favour of the investment firm(s) or credit institution(s) involved in the offer for the purpose of covering overallotments, under the terms of which such firm(s) or institution(s) may purchase up to a certain amount of relevant securities at the offer price for a certain period of time after the offer of the relevant securities, an option given by an issuer, normally but not necessarily for an equity issue, to the underwriters for the issue of additional securities to cover a short position generated by overallowing (the name derives from the first company (the Green Shoe Manufacturing Co.) to include such a feature in a public offering)