Software bug faulted in 3-hour Nasdaq crash


NEW YORK — Nasdaq OMX Group said Thursday that Nasdaq’s three-hour trading halt last week was due to an internal software bug and other technology issues triggered by problems at NYSE Euronext’s Arca exchange that led to the failure of a key backup system.

ARCA is the all-electronic exchange owned by NYSE, the parent of Nasdaq’s rival, the New York Stock Exchange.

Nasdaq said connection problems between Arca and the Nasdaq-run system that receives all traffic on quotes and orders for stocks on the exchange, known as the Securities Information Processor, led the processor to become overwhelmed.