Maturity by Maturity Bidding (MBM) A bond auction that allows bidders (who are underwriters) to submit bids for selected maturities in its issue, rather than requiring buyers to bid for the entire issue on an all-or-none (AON) basis.
Investopedia Says: This gives smaller underwriting firms more flexibility, allowing them to bid for part of the issue.
Related Terms: All or None - AON Bond Maturity Date Underwriter Venture Capital