Yasuko Oka Cuts Stake in J.S.B. (3480) to 0% | Large Shareholding Report

A large shareholding report (EDINET filing) shows that Yasuko Oka has reduced her stake in J.S.B. (3480) to 0%. The company manufactures and sells pharmaceutical and medical devices while conducting related research and development, with Oka's complete exit marking the disappearance of a multi-hundred-billion-yen shareholding position.

Stake Reduced from 32.73% to Zero Within One Month

Yasuko Oka first disclosed her holdings in J.S.B. on June 18, 2026, with a stake of 32.73%. By July 30, a change report showed the holding at 0%, meaning the entire position was disposed of within that month. The transaction was conducted off-market through a related-party trade with Ursa 4 Corporation as counterparty.

¥64.69 Billion Transfer at ¥9,000 Per Share

The transfer price was set at ¥9,000 per share for 7,187,800 shares. With J.S.B.'s market price at ¥9,230 on the disclosure date, Oka sold at approximately ¥230 per share below prevailing market levels. Proceeds from the transaction totaled ¥64.69 billion.

From Dominant Shareholder to Complete Exit

Prior to Oka's full exit, the largest disclosed shareholder was Kotsutransmission at 6.77%, followed by Nomura Securities at 0.01% and Neuberger Berman at 0%. Oka's 32.73% stake positioned her as the company's leading shareholder by a vast margin. That position has now completely unwound, fundamentally altering the shareholder structure going forward.

Elevated Valuation Metrics Reflected in Stock Price

At the filing date, J.S.B. traded at a PER of 36.9x and PBR of 4.56x. The high PER indicates the market prices the company's current earnings at a premium, while elevated PBR suggests the share price significantly exceeds net asset value. The 52-week range indicator at 100% confirms the stock trades near its 12-month high.

*Speculation: The exit from a long-standing stake in this medical device manufacturer may reflect a strategic portfolio reallocation or liquidity needs on the part of the major shareholder.