At least two big Uber stakeholders have agreed to sell part of their private shares to a group led by Japanese technology conglomerate SoftBank in a deal that lets investors cash out at a discount and could bring management stability to the San Francisco ride-hailing company. SoftBank said Wednesday that Benchmark Capital, Menlo Ventures and other early investors have confirmed intent to sell shares in the company. SoftBank’s offer was expected to be based on a reduced valuation of Uber. The company had been valued at $68.5 billion in a previous stock sale.