Facebook's stock is regaining some ground nearly a month after its rocky initial public offering.

The stock gained $1.02, or 3.7 percent, to close Thursday at $28.29. That's still down nearly 26 percent from Facebook's IPO price of $38. Facebook began trading on the Nasdaq on May 18.

Investors are concerned about its ability to keep increasing revenue and make money from its growing mobile audience, though many analysts hold positive long-term opinions.

Also on Thursday, a federal judge in Texas rejected a legal challenge to Facebook and leading investment banks over the IPO. A disgruntled shareholder had wanted the court to order depositions from Facebook's executives to find out if he had a case against the company. Facebook says it is pleased with the court's decision.