Masayoshi Son's fortune decreases by $4.6 billion as SoftBank shares plummet near 19%.

• On Monday, SoftBank Group shares plummeted nearly 19%, resulting in a significant loss of billions of dollars for founder Masayoshi Son's fortune, as part of a global stock market downturn.
• According to the Forbes real-time billionaires list, Son's net worth decreased by $4.6 billion on Monday alone.
• SoftBank's shares have only increased by 1.7% for the year despite Monday's price plunge, resulting in a loss of approximately $28.3 billion since the close of trade on Wednesday, according to CNBC calculations.

Nearly 19% of shares plummeted on Monday during a global sell-off, resulting in a significant loss of billions of dollars for Masayoshi Son's fortune.

The Japanese giant's shares have decreased since last Thursday, as Japanese equities dropped after the Bank of Japan raised its benchmark interest rate.

According to the Forbes real-time billionaires list, Son's net worth decreased by $4.6 billion on Monday alone.

The Nikkei 225 experienced a 12.4% loss, marking the worst day for the index since the "Black Monday" of 1987.

The stock of SoftBank had been performing well this year, reaching a new record high, until its recent declines. The recovery of the Vision Fund division and the significant increase in the share price of ARM Holdings, which is mostly owned by SoftBank, have contributed to the company's stock appreciation.

SoftBank's shares have only increased by 1.7% for the year despite Monday's price drop, resulting in a loss of approximately $28.3 billion since the close of trade on Wednesday, according to CNBC calculations.

This Wednesday, SoftBank will reveal its fiscal first-quarter earnings, with investors anticipating additional progress in the Vision Fund's recovery.

In June, the son who had been absent from the public eye for some time, returned to discuss his predictions about the future of artificial intelligence, which he believes will eventually be 10,000 times smarter than humans.