Midpoint Peg (M-Peg) Order Type
Midpoint Peg (M-Peg) is a non-displayed order type that is pegged to the midpoint of the NBBO, subject to the order’s limit price, if any.
M-Peg orders do not change their behavior during periods of quote instability, and when D-Peg orders exercise price discretion to the midpoint of the NBBO, M-Peg orders have priority over D-Peg orders.