The lawsuit was filed by Facebook investors on June 1 in the US District Court of Southern New York. It is based on reports that, ahead of the multi-billion dollar IPO, the banks overseeing the float informed major clients that they were reducing revenue estimates for the social network.
It is alleged that the information, drawn from a gloomy report compiled by an analyst from lead bank Morgan Stanley, was verbally conveyed to institutional investors, but not passed on to smaller investors during the IPO roadshow.
The suit alleges that Morgan Stanley, along with fellow IPO banks JPMorgan Chase and Goldman Sachs, failed to warn some investors that Facebook was "experiencing a severe and pronounced reduction in revenue growth" due to the major shift to mobile usage.
It says: "Defendants failed to disclose in the Registration Statement and Prospectus that, during the roadshow conducted in connection with the IPO, certain Underwriter Defendants reduced their second quarter and full year 2012 performance estimates for Facebook.
In response, a Facebook spokesperson said: "We believe the lawsuit is without merit and will defend ourselves vigorously."
The lawsuit follows a similar action launched last month, also naming the banks, along with Facebook and its founder and chief executive Mark Zuckerberg.
The new action, first reported by TMZ, alleges that Zuckerberg knew about the problems, as disclosure findings show that he sold 30.2 million shares in the company just after the stock went public, earning him a reported $1.1bn (£716m).
Separately, Morgan Stanley is being investigated in the US over the way it acted as lead bank on Facebook's IPO, which was the third largest in history and raised $16bn (£10bn) for Facebook.
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In trading yesterday on the US Nasdaq, shares in Facebook slumped to $26.44, down by more than 30% on the IPO price of $38, delivering real and paper losses of around $4.6bn to the new investors.
Bernstein Research analyst Carlos Kirjner said in a research note yesterday that it was "difficult to argue for owning the stock today", reports AFP.
Kirjner forecast a price of $25 over the next 12 months as being about right for Facebook, but added that further slowdown in the firm's revenue growth could "drive additional downside pressure on the stock".
The key issue is Facebook's warning that the shift to mobile use for its 900m members worldwide was cutting into its advertising revenues, where the company earns most of its money.
There are concerns over whether Facebook will be able to move fast enough to exploit the shift to mobile, or whether it will be able to unlock new revenue streams to appease jittery investors.