SoftBank Group Corp. on Wednesday reported its first quarterly operating loss in 14 years — ¥704.4 billion (about $6.5 billion) — after writing down the value of a string of marquee investments, including WeWork and Uber Technologies Inc.

The investment powerhouse also saw its group net profit halved for the six months to September, with net profit sinking 49.8 percent to ¥421.6 billion on an operating loss of ¥15.6 billion.

SoftBank swallowed a charge of ¥497.7 billion for WeWork, whose spectacular implosion turned the once high-flying shared-office startup into a Silicon Valley punchline.