New Delhi: Suspecting an uptick in the insider trading activities in the recent market rally, Securities and Exchange Board of India (SEBI)has enhanced its surveillance for possible violations of rules prohibiting trading based on prior and inside information. The market watchdog has come across over two dozen instances of major suspected violations of insider trading norms during the recent rally to new record levels above 21,000 level and the subsequent correction last week, a senior official said. While the suspicious trading activities have been noticed in the SEBI's routine surveillance of market activities, the regulator has decided to probe further into these cases and enhance its oversight for such matters going ahead, he added. Major violations have been suspected in trading of 25-30 stocks over the past few weeks, the official said, adding that suspicious activities have been noticed in many other shares also but those are minor in terms of trade value and nature. Insider trading relates to purchase or sale of shares by people having prior and privileged information about an upcoming development by virtue of they themselves or those related to them having holding a position in the company. As per the SEBI's Prohibition of Insider Trading Regulations, an 'insider' is defined as any person "who is or was connected with the company or is deemed to have been connected with the company, and who is reasonably expected to have access to unpublished price sensitive information in respect of securities of a company, or who has received or has had access to such unpublished price sensitive information." The stock market benchmark Sensex recently crossed 21,000 level to record its highest closing level at 21,004.96 points on November 5, after a sharp rally over the past few weeks, but has corrected about 900 points since then. The sentiments have been upbeat on the bourses, as also reflected in robust response to recent IPOs like Coal India. Insider trading activities increase during market rally and an environment of improved investor sentiments makes it easier for insiders to make money on the bourses, experts said. SEBI has systems in place to monitor unusual stock trends and suspicious activities are probed further for violations of norms including those regulating insider trading. Recently, SEBI slapped a penalty of 2 crore on Gujarat NRE Coke promoters A K Jagatramka and G L Jagatramka and their companies for indulging in insider trading. This is said to be the largest fine imposed this year for violations of insider trading norms. Later, the company said it would challenge the order. "Many cases of insider trading do go undetected. Only a very small percentage of the total number of insider trading cases comes under regulatory scrutiny," said Sudip Bandyopadhyay, Managing Director & CEO, Convexity Solutions and former CEO and Managing Director of Anil Ambani group firm Reliance Money. "It is difficult to specify the exact extent or percentage of insider trading. However, it does happen," he added. Bandyopadhyay said that the regulations are in well in place, but the difficulty lies in implementing them and detecting the offence. He advocated enhancement of powers of SEBI for seeking cooperation of other relevant regulatory authorities in matters of insider trading. Another market observer Arun Kejriwal, Director of KRIS, said that SEBI should keep a watch on dealing rooms of brokers and fund managers as also the companies' board meetings. "Insider trading is rampant.It appears that almost all spiked movement in Indian markets can be linked to insider trading," he added.