Twitter is on the verge of revealing the price of its stock offering, giving the popular messaging platform a value of around $US15 billion ($A15.8 billion), media sources say.

The Wall Street Journal and CNBC, citing unnamed sources, said the initial public offering (IPO) was likely to be at $US27 ($A28.51) a share, higher than the just-increased range of $US23 to $US25.

CNBC said three people familiar with the IPO indicated the underwriters had set the $US27 price, while the Journal said it was the most likely price, but that a range of $25 to 28 was still being debated.

Twitter plans to sell 70 million shares, with a possible over-allotment of 10.5 million. With that option, it would raise more than $US2.17 billion, or $US1.89 billion without the extra shares.

With the over-allotment, it would be the second-biggest tech IPO after Facebook’s $US16 billion effort last year and ahead of Google’s 2004 offer, which raised $US1.92 billion, according to research firm Dealogic.

Shares will trade under the symbol TWTR on the New York Stock Exchange.

Analysts said Twitter’s first price range at $US17 to $US20 a share appeared conservative and that the price was likely to rise because of heavy demand.

Still, Twitter is taking a cautious approach in its IPO, in contrast to Facebook, which flooded the market with shares and saw a sharp decline in the following months.

Twitter still must convince investors of its business model, having lost more than $US440 million since 2010.

But with 232 million users and growing, it is expected to be able to reach profitability by delivering ads in the form of promoted tweets, and from its data analytics.

The research firm eMarketer estimates Twitter will bring in $US582.8 million in global ad revenue this year, and nearly $US1 billion in 2014.