The National Stock Exchange has asked IT firm TCS, the main technology service provider for the exchange's main trading engine, to look into Monday's technical glitch which led to a halt in cash and derivatives trading on the exchange for almost three hours.
The leading bourse had stopped trading in cash as well as F&O (Futures & Options) segments following the glitch before resuming normal trade at 1230 hours.
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A source told Business Line there was a communication issue between NSE's order matching engine and data system layer, which could have caused the glitch.
The NSE had reconstructed the situation and concluded the communication issue could have led to multiple issues, leading to delay in resumption in trade, according to the Business Line report.
TCS has been providing key software and tech support to India's largest exchange since it started trading in 1994.
TCS declined to comment on the development.
The stock exchange will also seek clarity from market regulator Sebi on operational aspects.
The NSE handles about twice the stock volume of rival BSE and controls about 80 percent of the country's derivatives market, which is among the world's largest.
The exchange which has filed for an IPO in December end said an independent agency had found potential instances that some brokers were given unfair access to its servers.
The NSE said the agency had found certain employees may have been involved in providing that access, though it could not determine whether it constituted collusion.
The exchange also said its trading systems may have been "prone to manipulation," while noting that a lack of protocols on data retention meant that emails and information for some former employees were unavailable.
The findings threaten to cast a shadow over the NSE's IPO. Bankers had said the exchange could raise as much as $1 billion, making it potentially India's biggest since Coal India raised $3.5 billion in 2010.
The NSE said it had sent the report to Securities and Exchange Board of India (SEBI), which has to approve listing.