"If conditions on share price and a minimum of shares are not satisfactory for the SoftBank Group side, there is a possibility the SoftBank Group may not make an investment," it said in a statement.

Uber said this week that a planned deal with SoftBank and Dragoneer Investment Group was moving forward. The investment could be worth up to $10 billion, two people familiar with the matter have said..

SoftBank and Dragoneer are leading a consortium that plans to invest $1 billion to $1.25 billion in Uber, the mostly highly valued venture-backed company in the world, along with a purchase of up to 17 percent of existing shares in a secondary transaction.

Progress in the negotiations came after venture capital firm Benchmark, an early investor with a board seat in the ride-services company, and former Chief Executive Travis Kalanick struck a peace deal, reaching agreement over terms of the planned SoftBank investment.

The Japanese tech and telecoms firm has become a prolific investor in ride sharing firms such as China's Didi and India's Ola as it works to achieve SoftBank founder Masayoshi Son's vision of a future driven by artificial intelligence and interconnected devices.

(This story adds dropped word in last paragraph.)

(Reporting by Sam Nussey; Editing by Edwina Gibbs)