SoftBank's new stock trading details raise concerns of financial stability

Firm reveals details of controversial derivatives trading

SoftBank Group provided new details about its stock and options trading program, a controversial effort that roiled markets and raised concerns about the Japanese company’s financial stability.

SoftBank said the fair value of its futures and options positions came to $2.7 billion at the end of September, suggesting its positions are more conservative than originally feared. That included long call options on listed stocks worth $4.69 billion and short call options on listed stock with negative $1.26 billion of value, the company said . 

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