SoftBank Group Corp. plans to cut at least 20% of staff at its Vision Fund investment arm, Bloomberg reported on Friday, after Chief Executive Masayoshi Son pledged to cut costs after a record $50 billion loss at the unit in the half year to June 30.

The conglomerate will cut at least 100 positions and could announce the reductions as early as this month, Bloomberg reported, citing unnamed sources.

A SoftBank spokesperson said: "As Masa said at our most recent earnings (briefing), we are reviewing the organization size and structure. However, nothing has been decided yet."

SoftBank has scaled back investing activity, with Son last month saying he would cut Vision Fund's workforce and reduce costs across the group. "We need to cut costs with no sacred areas," Son said.