Under the deal taking shape, the sources said Softbank would buy some $12 billion worth of Sprint shares and spend another $8 billion on new Sprint securities. The Japanese firm would initially buy $3 billion of bonds convertible into Sprint stock at $5.25 a share, the Wall Street Journal reported, citing people familiar with the matter. It would also buy $5 billion in stock directly from Sprint, and offer $7.30 a share for stock it buys in the public markets. Sprint closed on Friday at $5.73.