Nanex ~ EDGE Quote Halt
On Monday, April 16, between about 15:16:20 and 15:27:55, quotes stopped updating
from EDGE in stocks between approximately SO through TZ.
SPY was one of these stocks. You can see in the charts below that trading was unaffected,
but the stale EDGE quote caused the
NBBO to cross severely.
SPY 1 second interval chart showing EDGE Quotes and Trades.
SPY 1 second interval chart showing EDGE and EDGE-X Quotes and Trades.
Note how EDGE-X (blue) was not affected and reflects where other exchanges
were quoting and trading.