Facebook shares have fallen for the third consecutive day.
The stock fell 1.03 dollars, or 3.8%, to close at 25.87 dollars - 32% below its initial public offering price of 38 dollars.
It is the stock's lowest closing price to date.
Earlier on Tuesday, it went as low as 25.75 dollars.
Since Facebook's stock began trading publicly on May 18, it has fallen on eight of the 12 trading days.
There have been concerns about Facebook's ability to keep increasing revenue and make money from its growing mobile audience, though many analysts hold upbeat long-term opinions.
The initial public offering (IPO) was highly anticipated and was supposed to offer proof that social media is a viable business and more than a passing fad.
Facebook, based in Menlo Park, California, has nearly a billion users.