Masayoshi Son is now personally on the hook for about $4.7 billion on side deals he set up at SoftBank Group to boost his compensation, after mounting losses in the company¡¯s tech portfolio wiped out the value of his interest in the second Vision Fund.

Over the years, the Japanese billionaire¡¯s controversial personal stakes in SoftBank¡¯s investments drew fire from investors, who pointed to the mix of personal and company interests as a corporate governance concern. Son ¡ª who holds a more than 30% stake in SoftBank ¡ª has denied there was a conflict of interest and said it was remuneration for his investment expertise, in lieu of investment fees.

The move has backfired, enveloping Son¡¯s personal finances in the downside of the world¡¯s biggest tech investor¡¯s bets. Son was down more than $4 billion on his side deals through the June quarter, Bloomberg News reported earlier.