01/09/2013 16:52 EST | Updated 03/11/2013 05:12 EDT

Facebook shares gain 5% on mystery announcement

Shares in social networking giant Facebook closed above $30 US for the first time since July on Wednesday amid speculation about an announcement next week.

Its shares ended trading at $30.59, up $1.53, or 5.26 per cent, on heavy volume on the Nasdaq.

They are up by 60 per cent since hitting a low of $19.21 in November.

Nonetheless, Facebook is still 20 per cent below its initial public offering price last May of $38.

Late yesterday it sent invitations to the media for an event on Tuesday at its headquarters in Menlo Park, Calif., prompting speculation it plans to announce a major new product.

The invitation said simply, "Come see what we're building." It provided no other details.