(Bloomberg) -- The sudden collapse of Silicon Valley Bank looks set to increase scrutiny of SoftBank Group Corp. investments, and possibly drive its share price to Masayoshi Son’s pain point.

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The US tech lender’s failure has fueled investor concern over the exposure to startup firms in the SoftBank Vision Funds. SoftBank shares have plunged 13% in four sessions to below 5,000 yen and are nearing a level that some see as Son’s threshold for announcing a buyback.

The SVB crisis has trained a spotlight on private tech investments, especially following a flight from highly valued stocks as the Federal Reserve started tightening last year. While SoftBank said it expects almost no impact from the US lender’s collapse, few investors think it will emerge unscathed.

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“Startups’ funding conditions were getting tougher and the window for IPOs was narrowing even before SVB’s failure,” said Tetsuro Ii, chief executive at Commons Asset Management Inc. “One thing that is certain is that things will get worse.”

SoftBank may have to mark down the value of private companies it has invested in. That’s on top of the slide in the company’s publicly traded investments, most notably Alibaba Group Holding Ltd., whose shares are down 30% from a January high amid a selloff in Chinese stocks. SoftBank declined to comment for this article.

That will not go down well with investors after losses that have helped drive SoftBank down 30% from a November peak. The company has posted a cumulative net loss of about $22 billion over the past four quarters amid declines in portfolio holdings including WeWork Inc.