LONDON, May 11 (WNM staff) - The SoftBank Vision Fund is close to striking a £3billion deal with a British financial technology firm advised by David Cameron, The Mail on Sunday reports.The deal could be announced as early as Monday, a city source told Reuters.

City sources said SoftBank, which is led by maverick entrepreneur Masayoshi Son, is in negotiations with former Morgan Stanley and Citigroup banker Lex Greensill over investing about £500million in his firm Greensill.

Greensill is a specialist in supply-chain finance, where businesses raise funding backed by their payments to suppliers.

The investment, which is being led by the $100billion (£77billion) SoftBank Vision Fund, would value the seven-year-old online finance firm at about £3billion. According to the Financial Times, the deal would give the Vision Fund a 15-20 per cent stake in Greensill.

Greensill estimates the largely untapped market for working capital finance at $55 trillion, Bloomberg reports. The money from Vision Fund should help it "accelerate its expansion and develop new technologies to make more capital accessible to its clients", A person quoted by Bloomberg sdays. It is supposed also speed up its recent entry into Brazil as it advances plans to enter other markets, including China and India.