This data is surprising, but not inconsistent with the widely held belief of widespread insider trading. In other words, there appears to be many people doing low level insider trading, or even digging out some informational advantage even without any illegality. But few, if anyone, is doing insider trades in millions of shares or even a fraction of that number. And I can think of two reasons which come to mind why this is the case in India. First, we don’t have the class of investors who exist in the US, classic hedge fund managers who have a strong incentive to beat the index return. Since it is difficult to beat the market, and since the managers get to keep 20% of the profits of investors’ money there is a strong incentive to commit insider trading. With the size of the funds which many of these managers invest running into billions of dollars, they can’t possibly do insider trading in a few thousand shares — they must necessarily do it in very large numbers. Thus the chance of getting caught also increases substantially. Second, the Indian system is far more transparent and the audit trail is very clear. As opposed to more opaque systems of holding in ‘street names’ for instance in the US where brokers hold shares on behalf of investors in their own name, in India every investor buying a single share must provide an income tax PAN card number and shares must be held in their own name. The complete trail of purchase of securities and transfer of funds ensures that promoters and senior management are either not committing illegalities or are doing it by dividing it through dozens of other people, each one buying not more than a few hundred or thousand shares. Given the easy access to phone records (not phone taps) it is not impossible to connect the dots between these people.