Shares of Facebook (Nasdaq: FB), the No. 1 social networking site, vaulted 6 percent in pre-market Wednesday trading following CEO Mark Zuckerberg's acknowledgement of "disappointing" performance since the highly touted May 17 initial public offering.

Facebook shares rose $1.16 to $20.59 in pre-market activity, trimming the loss in post-IPO activity to only 49 percent.

Zuckerberg, 28, spoke Tuesday to a conference of TechCrunch, a unit of AOL Inc. (NYSE: AOL), where he said, "We care about our shareholders," and said the Menlo park, Calif., site was building "a mission and building a business." He said the company would improve its search function, likely wouldn't develop a smartphone and urged customers and investors to judge its performance, not stock price.

TechCrunch posted video of the Facebook CEO's remarks on its website.