One of the two principal methods of conducting an initial public offering (IPO), in which the underwriting syndicate doesn’t buy shares directly from the issuing company but only does its best to market the shares to public investors. In other words, the syndicate of investment banking firms merely facilitates the IPO process by acting as an agent between the company and investors, and doesn’t assume, as opposed to the method of firm commitment, the risk of buying all the shares directly from the company.

The term “best efforts” is used in American English and “best endeavors” is used in British English.