Finnish mobile phone maker Nokia
One of the sources, who declined to be named because talks were still in progress, said a deal could come as early as this week but there was still a chance it could fall through due to the difficulty of carving the unit out of Nokia.
Vertu makes some of the world's most expensive mobile phones, often featuring crystal displays and sapphire keys. The phones can cost more than 200,000 pounds due to previous metal components, although they are not the most technologically advanced phones.
Permira, another private equity group, had previously been in talks to buy Vertu but did not make an offer, according to sources.
Nokia, once the world's leading mobile phone company but is now struggling with falling market share, has said it plans to sell "non-core assets".