Some analysts had estimated Twitter's market value might be as high as $20 billion.
The investment bankers handling Twitter's IPO could raise the price yet again before the IPO is priced Wednesday evening. The shares are scheduled to begin trading Thursday on the New York Stock Exchange under the symbol "TWTR."
Twitter said in its Monday regulatory filing that it still plans to sell 70 million shares. If all of those shares are sold, the offering's underwriters can buy another 10.5 million shares.
At $25 per share, Twitter's market value would be around $15.6 billion. Twitter's value is based on 625.2 million outstanding shares expected after the offering, including restricted stock units and stock options.
Twitter is trying to avoid the trouble that plagued another high-profile IPO completed nearly 18 months ago by Facebook Inc., one of its biggest rivals.
Facebook's IPO was marred by technical glitches on the Nasdaq Stock Exchange in May of 2012. As a result, the Securities and Exchange Commission fined Nasdaq $10 million, the largest ever levied against an exchange. Those problems likely led Twitter to the New York Stock Exchange.
Twitter also said in its filing that it received a letter from IBM accusing it of infringing on three of its patents. The letter asks Twitter to take part in settlement negotiations, but Twitter said in its filing that it believes it has a "meritorious defense" to the allegations.
Unlike many large technology companies, Twitter has a small portfolio of patents to help combat allegations of intellectual theft. As of Sept. 30, Twitter had been issued just nine patents and has applied for 95 others. In contrast, IBM was awarded nearly 6,500 patents last year alone.
Meanwhile, the company faces skepticism from potential investors and the broader public, according to an Associated Press-CNBC poll.
According to the poll released Monday, some 36 percent of Americans say buying Twitter shares would be a good investment, while 47 percent disagree. Last May, ahead of Facebook's IPO, 51 percent of Americans said Facebook Inc. would be a good investment. Just 31 percent didn't agree.
And surprisingly, 52 percent of people ages 18 to 34 say investing in the Twitter's stock is not a good idea.