SoftBank Group Corp. has agreed to sell a large portion of its stake in InMobi Pte back to the mobile advertising company for about $250 million, unwinding much of an investment that created India’s first unicorn in 2011.InMobi will repurchase the shares to reduce SoftBank’s holding to less than 10% from more than 30%, people familiar with the matter said, asking not to be identified discussing private information. The transaction is part of a broader cap-table reshuffle as InMobi prepares for a potential ...