A day after its barometer Nifty recorded biggest single-day loss, country's leading bourse National Stock Exchange on Tuesday asked investors to tread carefully before investing in equities and keep away from rumours and advertisements promising large returns.

"Do not be attracted to stocks promoted by internet websites, research reports, tips etc unless you have done adequate study of the company," NSE said on Tuesday.

This followed a sharp fall of 270.70 points in the NSE's 50-share barometer index Nifty yesterday, which is its biggest ever single-day plunge.

The 30-share Sensex, the benchmark index of another leading bourse BSE, also fell by 769 points -- the second highest single-day fall in its over two decade history.

Even today, a high level of volatility was seen on the bourses with the Nifty swaying 164 points between its intra-day high and low levels.

The Sensex recorded a swing of over 300 points in the intra-day trade. It moved at least 20 times between the positive and negative territories during the day's trade. In an advertisement published in leading newspapers today, NSE asked investors to "do a thorough evaluation before trading in any security".

While asking investors to check information like price-volume data, financials and shareholding patterns before investing, the exchange asked them to be cautious of stocks that show a sudden spurt in price or trading activity without a change in the fundamentals of the company.

It also asked investors not to be misled by rumours or inducements/advertisements that promise large returns and to invest their time before investing their money.