By Savio Shetty and Abhirup Roy
MUMBAI (Reuters) - A technical glitch shut down India's National Stock Exchange (NSE) for five hours on Monday, dealing the country's biggest stock exchange an embarrassing blow ahead of its plans to list as volumes on a rival bourse surged.
Trading resumed fully on Monday afternoon, with quotes for individual stocks finally restored with just over an hour of trading left. The long disruption frustrated traders and put a spotlight on the exchange at an awkward time.
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The NSE's plans for a listing that bankers say could raise as much as $1 billion have been delayed by a regulatory probe due to its disclosure in December that some brokers may have been provided unfair access to its servers in recent years.
The NSE did not provide a reason for Monday's disruption, attributing it to "technical reasons." Two sources familiar with the matter said it was an internal issue, ruling out any external cyber attack or hacking.
"The technical team of NSE is looking into the issue," the exchange said in a statement.
The Finance Ministry has asked NSE and the market regulator, Securities and Exchange Board of India, to submit a report within the next two days on the reasons for the disruption, a senior finance ministry official said.
That will further raise scrutiny of the NSE, which submitted an application for an initial public offering (IPO) in December but has yet to win approval for the listing from SEBI.
The disruption, which affected traders from the market open, surpassed a three-hour disruption suffered by the BSE in July 2014 because of a network outage.
Its rival BSE was operating normally on Monday and saw a surge in trading volumes as shares hit new highs.
The NSE was able to resume trading for cash, as well as stock indexes and futures, when markets re-opened at midday, but multiple dealers said individual stocks were not updating normally or were suffering wide gaps in bid and offer prices.
The problem was not resolved until well into the trading session with just over an hour left in Monday's session.
The NSE's broader index rose as much as 1.2 percent to a record high, surpassing its previous milestone set on June 6, though trading remained largely hampered. Volumes were at only about 6 percent of the average trading volumes seen last week, according to Thomson Reuters estimates.
In contrast, a rival index run by the BSE - the S&P Sensex - also rose as much as 1.2 percent to its own record high, with the exchange enjoying about 50 percent more trading volumes than the average last week.
The NSE, however, is by far the larger index of the two, and hence any disruption is felt more widely.
"For us the main concern is liquidity for the stocks that we are operating in today because only BSE is on," said Gautam Sinha Roy, a fund manager at Motilal Oswal Asset Management Co.
"It is a hassle."
(Writing by Rafael Nam; Editing by Jacqueline Wong)