The parallels between hotel chain unicorn Oyo and office-sharing unicorn WeWork -- whose value plunged from $47 billion to "a pretty high probability of being a zero," according to a veteran investor after seeing its IPO filing -- point to their common DNA and raise similar questions. SoftBank Group, directly and through its Vision Fund, is heavily invested in both. Three symptoms stand out: first, a questionable business model; second, Oyo's numbers, and in particular its shockingly small revenue; and third, a heady valuation propped up by a financial maneuver previously used by SoftBank family members.