Which type of underwriting means the underwriter is not responsible for any unsold securities?

In best efforts underwriting, the underwriter agrees to sell as much of the security issue as possible but does not guarantee the sale of the entire issue. This means that the underwriter is not responsible for any unsold securities; if they cannot sell all the securities, the issuer will only receive funds for the securities sold, and any unsold securities remain with the issuer. This arrangement is typically less risky for the underwriter, as they do not have to take on inventory risk.

This contrasts with firm commitment underwriting, where the underwriter buys the entire issue, taking on the risk of any unsold securities, and then resells them to the public. In standby underwriting, the underwriter agrees to purchase any unsold shares during a rights offering, effectively placing their responsibility for any unsold securities. All-or-none underwriting requires that the entire issue be sold or the offering is canceled, making it a more rigid form of underwriting.