Wolff states "Using the secondary market for shares to mark enterprise value is a very difficult and opaque process. It is a rumor-rich and special-share-class soup. That said, Twitter is up since the Facebook IPO and is now valued at northward of $11 billion. This makes sense as growth in users and new monetization efforts are both yielding fruit and pointing toward a good 2013 for Twitter.”
According to The Guardian, "a new round of funding in 2011 valued the company at $8 billion, and its value rose to $10 billion on secondary markets, before dropping a bit following Facebook's dismal IPO in 2012."
“Twitter's value has also been swollen by speculation that Apple is interested in acquiring the company,” says Greencrest analyst Max Wolff.
Backing up comments made late last year by chairman Jack Dorsey, “You can think of an IPO as an exit or a goal, or you can think of it as more of a milestone. For us, it's a milestone,” he said.