Nasdaq OMX Group said human error left the U.S. exchange unable to transmit index values for nearly 45 minutes on Tuesday, leading to a temporary halt in options trading on some stock indexes.
Index values for the Nasdaq Composite, Nasdaq 100, PHLX Semiconductor, PHLX Oil Service Sector and PHLX Housing Sector were unavailable to the public for almost 45 minutes.
The lack of data forced the Nasdaq to halt options trading in those indexes on Nasdaq's PHLX and Nasdaq Options Market exchanges. Trading in those options was halted around 12:15 p.m. and restored about 1 p.m. EDT.
The Nasdaq 100, one of the indexes that was briefly unavailable, is the benchmark for the PowerShares QQQ Trust exchange-traded fund, one of the most heavily traded ETFs in the U.S. market.
"The disruption was caused by a human error performing an operational function which resulted in the incorrect delivery of data ...," Nasdaq said.
The error "limited the ability of the system to distribute index data," the exchange said.
The exchange said its Global Index Data Service "experienced a brief disruption of service" that did not affect equity exchange operations. Nasdaq was still able to calculate index values, just unable to distribute them.
The exchange has struggled to repair its reputation following some high-profile interruptions, most notably a total exchange shutdown for three hours on August 22 and last year's botched initial public offering of Facebook Inc.
"I don't know what it is, but it appears they have an unusual proportion of technical problems there," said Stephen Massocca, managing director at Wedbush Equity Management LLC in San Francisco.
"You would think they would be on their tippy-toes making sure everything was absolutely correct over there ... at this point, it's more than just luck."
The Securities and Exchange Commission said it was monitoring the situation.
"We have been in contact with market participants as is our standard practice and monitoring developments as appropriate," said SEC spokesman John Nester.
According to options analytics firm Trade Alert, in NDX, 4,932 calls and 14,000 puts traded through 3:04 p.m. with less than one hour left of trading, below the recent combined daily average of 42,000 contracts.
(Reporting by Ryan Vlastelica, Chuck Mikolajczak and Sarah Lynch; Editing by Chizu Nomiyama, Andre Grenon, Tim Dobbyn)