NBBO
MarketsDefinition
National Best Bid and Offer. The highest bid and lowest ask across all US exchanges. Reg NMS requires retail orders to be filled at NBBO or better.
NBBO is updated continuously — millions of times per day for liquid names. Brokers route orders to wholesalers (Citadel Securities, Virtu) who guarantee NBBO-or-better execution; this is why retail commissions are zero.
NBBO is updated continuously — millions of times per day for liquid names. Brokers route orders to wholesalers (Citadel Securities, Virtu) who guarantee NBBO-or-better execution; this is why retail commissions are zero.