Broadband phone company Vonage has said it has raised $250m (£142m) to help finance the expansion of its network.
Vonage has more than a million customers
The US firm, which enables people to make calls over the web using their home phones, said it acquired the funds from a group of private investors.
Vonage is one of a number of companies focusing on internet telephony, known as Voice Over Internet Protocol (VoIP).
The financing could be the private firm's last before it goes public, The Wall Street Journal reported on Sunday.
Vonage managers are understood to be exploring the possibility of floating the company on the stock market.
However, a deal which could see the firm sold to a separate buyer could also materialise, the newspaper said.
Vonage has more than a million customers in the US and recently launched operations in the UK.
Investors are increasingly excited at the prospects for growth among VoIP companies, which offer users phone calls at substantially lower prices than traditional fixed-line firms.
In September, online auction giant eBay agreed to buy internet telephone firm Skype Technologies for $2.6bn.
The latest round of investment in Vonage brings the total amount raised by the company to $658m.