The Japanese tech group booked a $5.2 billion quarterly loss on Thursday (November 9) - its fourth straight quarter in the red.

It took a hit from the bankruptcy of the once high-flying WeWork, a company once valued at $47 billion.

SoftBank also wrote down the value of tech investments.

The results show the unpredictability of founder Masayoshi Son's strategy of betting big on often risky start-ups.

The Japanese conglomerate said it was squeezed by weakness in the yen that drove up costs on its dollar-denominated debt.

The $5.2 billion net loss for the three months to end-September compares to a near $20 billion profit a year earlier.

Its Vision Fund investment unit, meanwhile, booked an investment profit of $141 million in Q3, after posting a $1 billion profit three months earlier.

SoftBank said it believed the group had seen the worst and was moving towards profitability.

The downbeat results came even as it managed to achieve the initial public offering of its chip designer Arm.

Softbank said Arm would be the new driver of value for the investment giant.