Shares in Facebook leap by almost a third after it beat earnings expectations with stronger-than-expected mobile ad sales.
On Wednesday, the social networking giant had reported profits of $333m (£217m) in the second quarter.
When trading began in New York, Facebook shares were 25.6% higher at $33.30, the highest since May 2012.
Facebook, which is the world's largest social networking company, floated on the Nasdaq at $38 a share last year.
Following the release of the latest results, at least 16 brokerages raised their price targets for the firm.
"Facebook has discovered the formula to begin significantly extracting value from its 1.16 billion global users," said JMP Securities analyst Ronald Josey.