Nasdaq on Thursday took partial blame for the three-hour shutdown of the country's second largest exchange last week, which it blamed on "a combined series of technology events."
But it also pointed to problems that arose from NYSE Arca, an electronic exchange trading Nasdaq-listed shares that is owned by larger rival NYSE Euronext.
In its most extensive remarks since the August 22 shutdown, Nasdaq OMX, which operates the exchange, took responsibility for some of the technical glitches, saying a number of them "were clearly within the control of Nasdaq OMX."
But it said that other problems behind the shutdown are "more endemic" to the overall market and "will require a broader industry-wide effort to resolve."
"As the Securities Information Processor (SIP) for NASDAQ stocks, we are responsible for them, regret them, and intend to take all steps necessary to address them to enhance stability and functionality of the markets," the company said in a statement.
"NASDAQ OMX is deeply disappointed in the events of August 22 and our performance is unacceptable to our members, issuers and the investing public."
Nasdaq described a series of "unprecedented events" that overwhelmed the capacity of its SIP system, which consolidates and disseminates prices for Nasdaq-quoted securities that are traded on a group of smaller exchanges.
It said that on August 22, its system received more than 20 connect and disconnect sequences from the NYSE Arca which "consumed signficant resources," while the system was "further eroded" by a stream of quotes for inaccurate symbols from NYSE Arca.
"Both of these actions served to degrade the system," it said.
"The confluence of these events vastly exceeded the SIP's planned capacity, which caused its failure and then revealed a latent flaw in the SIP's software code," Nasdaq said.
Nasdaq suspended the system after concluding that a shutdown of the system was "in the broader public interest."
Nasdaq also pledged to improve its communication with customers and the broader public during market events.
A spokeswoman for NYSE Euronext declined comment on Nasdaq's references to NYSE Arca's role in the problem.