All or none underwriting allows the issuing corporation to contract for the sale of all shares. If any shares remain at the end of the underwriting process, the underwriting is cancelled. Underwriters cannot deceive investors by stating that all of the securities in the underwriting have been sold if it is not true. (Investopedia)

The Board is of the view that an initial "when, as and if issued" confirmation of a transaction in a security which is the subject of an "all or none" underwriting may be sent out prior to the time a formal bond purchase agreement is executed. ( Municipal Securities Rulemaking Board)

There is one last variation. That is called an 'All Or None Underwriting'. Under this type of underwriting the underwriter agrees to do his best to sell the entire issue by a certain date. All of the proceeds go into an escrow account. If the securities are not all sold by the certain date, the money is returned to the purchasers and the issue is canceled. (Initial Public Stock Offering)