NBBO Stability for U.S. Equities during the first 19 seconds of every trading
day between January 1, 2006 and January 30, 2012.
Chart shows the percentage of stocks with quote updates that had a stable
NBBO (National Best
Bid or Offer).
A stable NBBO has a spread (Ask price - Bid price) that doesn't flutter or change during that second.
Older dates colored towards the violet end of the spectrum, newer dates towards the
More on NBBO Stability.