Trading in the mini-indices of Sensex and Nifty got off to a decent start on Tuesday with both the products attracting trading interest from investors.

But the big surprise on the first day of trading was the performance of underdog `Chhota' Sensex of the Bombay Stock Exchange (BSE).

The mini-Sensex clocked more trading turnover (in terms of value) than National Stock Exchange's (NSE's) mini-Nifty on Tuesday, taking market men by surprise.

The total trading turnover on mini-Nifty stood at Rs 65.66 crore whereas the `Chhota' Sensex was able to attract a volume for Rs 116.18 crore.

In terms of number of contracts transacted, however, NSE's mini-Nifty saw a bigger volume of 1,06,800 contracts compared to Chhota Sensex's 56,825.

"We were determined to ensure that Chhota Sensex became more popular with our clients in the first day itself. Traders may also have spotted big arbitrage opportunity between the Sensex derivatives and mini-Sensex, given that the F&O (futures & options) in BSE is less liquid compared to the NSE's derivatives segment," said a BSE member.

For instance, on Tuesday, the total trading volume in BSE derivatives was just Rs 1,126.2 crore, compared to NSE's nearly Rs 50,000 crore. The trading volume in Nifty futures contracts alone was Rs 10,240 crore compared to Sensex futures' Rs 1,010 crore.

"Surely, there may not have big arbitrage opportunity between the Nifty and the mini-Nifty contracts. In a highly liquid market, there exists no arbitrage opportunity. And, hence the lower trading volume," he said.

Analysts expect institutional investors to spot the arbitrage opportunity between the `bada' and the `chhota' indices, rather than retail investors. "Retail investors always follow the trading tips given by their dealers. They also follow big trades," explained another dealer.

NSE waives transaction charges on three indices. Meanwhile, in a circular to members, the NSE on Tuesday said it was extending the transaction charges waiver for derivatives trading in Nifty Junior, CNX100 and Nifty Midcap50 till March 31 this year.

Additionally, if a trading member trades at least 10 contracts on the futures sub-segment in any of these three indices in a month, transaction charges waiver will be provided on Nifty futures turnover to the extent billable in that calendar month.

Since its entry into F&O segment, the three NSE indices were not able to attract big volumes. For instance, the derivatives volume in CNX100 is just Rs 6 lakh on Tuesday. On Nifty Junior, the trading volume stood at Rs 8.58 crore and on Nifty Midcap50, the trading volume was Rs 2.46 crore.