The CBI has arrested former National Stock Exchange (NSE) group operating officer Anand Subramanian, following his questioning in a 2018 case related to the alleged abuse of the server architecture of the exchange for allowing access to a private company to the data ahead of other brokers.

“Mr. Subramanian was arrested in Chennai on February 24 night. He was earlier questioned for three days,” said an agency official, confirming the development.

The CBI has collected the relevant documents from the Mumbai office of the Securities and Exchange Board of India (SEBI) and had also recorded the statements of former NSE managing directors Chitra Ramkrishna and Ravi Narain a few days ago, after look-out circulars were issued against them and Mr. Subramanian.

In May 2018, the CBI had registered the First Information Report against OPG Securities, which is a stock-broker, and others. Unknown officials of the SEBI and the NSE were also under the scanner for connivance.

As alleged, the company had been given illegal preferential access to the market data feed from the exchange’s server, via an algorithmic trading software package named “Chanakya”, ahead of other brokers. During 2010-12, the company got access to the NSE’s server architecture through “co-location” facility, which allowed it to log in first to the server before other brokers.

On February 11, the SEBI had levied a penalty on Mr. Subramanian and the two former NSE managing directors for several violations, including the irregularities in his appointment as a chief strategic advisor and his re-designation as the group operating officer and advisor to the then managing director of the exchange.

According to the SEBI order, Mr. Subramanian also knew the unknown “yogi” with whom Ms. Ramkrishna had been sharing internal papers of the NSE and on whose instructions she took various decisions. He was a major beneficiary of the yogi’s purported recommendations to her.

In January 2013, Mr. Subramanian was offered ₹1.68 crore for the post of chief strategic advisor in the NSE, when his last drawn salary was ₹15 lakh in a government corporation. He got increments in quick successions and his compensation had increased to about ₹5 crore by 2016. During the check period, he also made several visits abroad.

Earlier, the Income-Tax Department had carried out searches on the premises of Ms. Ramkrishna and Mr. Subramanian in Mumbai and Chennai, on suspicion of tax evasion.