During this period, NYSE Arca sent multiple bursts with each connect and disconnect, topping more than 26,000 quote updates per-port, per second as it attempted to reconnect. By comparison, a typical August day for NYSE Arca would peak at less than 1000 messages per-port, per second. The events of August 22 were 26 times greater than the average per-port, per-second activity.
As for the message volumes, the spokesman said the impact of the additional quote traffic has been modest. "As our systems are designed to handle message volumes with minimal throughput degradation, we're seeing member firms submit marketable orders in active securities and we've received feedback that the impact of additional quote traffic at the NBBO is modest as member firms have also already prepared to handle any active periods of messaging volumes," the spokesman wrote.So, if Nasdaq sends 26,000 quotes in one stock (therefore 1 port) in 1 second, it's considered "modest". But when NYSE-Arca sends messages at that rate, it causes a 3 hour black-out?
More recently, on both May 21 and May 22, 2013, there were 3 seconds back-to-back with
over 27,000 quotes in each second in Microsoft. On May 29, 2013, there were 2 seconds
of 27,000 quotes each second in Microsoft.
There were no black-outs on any of those days.
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