Facebook's stock slumped 5.2% in trading today to $32 a share, following the firm's listing on the Nasdaq stock exchange at $38 last Friday in the third biggest share sale in US corporate history.
Yesterday, the share price was down 11%, as the heady excitement that surrounded the company's initial public offering (IPO) was replaced by wary scepticism.
The shares are currently trading at around $33.
When Facebook went public last week, the social network, which has 900m members worldwide, was valued at an eye watering $104bn (£66bn).
The shares peaked at around $43 at the start of trading, valuing the firm at $115bn, but then dropped back to just below the original IPO price.
Facebook has revolutionised the way people socialise online, but there have also been concerns over how it will transfer the massive user base into sustainable revenue generating opportunities.
Facebook managed to generate just $1bn in profit last year, and the business is almost wholly reliant at the moment on online advertising for its income.