By CCN: Just months ago, Japanese tech behemoth Softbank was on top of the world, and CEO Masayoshi Son added $5 billion to his net worth following a well-timed stock buyback program. But fortunes have turned for Softbank and Mr. Son. Softbank stock has slumped nearly 20 percent since its April highs, its Uber investment is looking shaky, and new fundraising efforts are failing. Meanwhile, Mr. Son revealed his monstrous losses from a disastrous bitcoin bet.