New Delhi (Agecnies): Suspecting foul play in the crashing of stock markets over the past few months, SEBI is probing at least 25 entities, including brokerage firms, FIIs and mutual funds.

The initial investigations have revealed the possibility of at least three 'bear cartels' operating in the stock market and SEBI has decided to seek inputs from the exchanges and various market entities on trading patterns of the affected stocks over past three months, sources said.

'Bear cartel' refers to a group of market manipulators working in concert to hammer down certain stocks, either to buy them at lower prices or at the behest of corporate rivals.

These cartels are suspected to have manipulated, in concert or separately, share prices of over 100 companies, including the blue-chips, over the past few months.

Most 'victims' are from mid-cap and small-cap segments. The BSE benchmark Sensex has fallen by over 3,000 points, or more than 15 per cent, since its record closing high of about 21,004 points on November 5.

The fall is even more in total investor wealth, measured in terms of cumulative market value of all listed stocks, at about 20 per cent with a loss of about Rs 15,00,000 crore.

This is because of the fall was steeper in stocks other than the 30 Sensex constituents, including those from mid-cap and small-cap segments.

 Sources said that SEBI suspects that these bear cartels together could comprise of more than 25 entities, including individual brokers and people related to brokerage houses, foreign funds operating as FIIs and domestic mutual funds.

A senior official said that entities under the scanner include people working with certain brokerage firms, FIIs and mutual funds, while a few others are suspected to be related to the employees of these firms. He, however, declined to disclose any names as it would hamper the investigations.

SEBI suspected the foul play after it noticed possible irregularities in the market dealings while analysing the data captured by its in-house DWBIS (Data Warehousing and Business Intelligence System) software, which is used extensively in its various investigations.

Adding to the market regulator's suspicion, promoters of about a dozen companies - including Anil Ambani group that has six listed firms - have filed complaints with it regarding the possible role of bear cartels in hammering their stocks.

 Hit hard by a heavy sell-off in its stocks, Anil Ambani group said it blamed a bear cartel and corporate rivals for the plunge, and sought a SEBI probe.

It alleged that the cartel could have caused a loss of over Rs 3,00,000 crore in infrastructure stocks over the past few weeks, while claiming to have identified some rogue stock brokers, whose names it has submitted to SEBI.