Masayoshi Son has quietly tightened his grip on SoftBank Group during a tumultuous market downturn, edging closer to the point where he could bid to take the world’s largest technology investor private.

The billionaire now owns more than a third of the company he founded, after aggressive buybacks in the last two months reduced SoftBank’s outstanding stock by almost 90 million. Son’s stake in the company rose to 34.2% from 32.2% as of the end of September, according to Bloomberg calculations, confirmed by the company. That’s up from 26.7% as recently as March 2019.

Under Japanese law, Son gains additional rights after breaching one-third ownership. The 65-year-old wields more control over asset sales, some buybacks, mergers and corporate bylaws by having the power to veto any special resolution put before shareholders by activist investors.