SYDNEY — Shares in Mesoblast Ltd surged 8.82% on the Australian Securities Exchange, climbing 19.5 cents to close at $2.405, as the Melbourne-based regenerative medicine company clawed back a significant portion of the losses it suffered at the end of last week following a securities filing that had briefly rattled investors.

The rebound came just one trading session after Mesoblast shares were the worst performer on the ASX 200 on Friday, tumbling 7.14% to $2.21. That decline followed a substantial holder notice disclosing that U.S. custodian bank State Street Corporation had accumulated a 5.1% stake in the company. According to reporting on the filing, the position was largely attributable to routine stock-borrowing and securities-lending activity rather than a conventional long-term investment, a detail that appeared to unsettle some investors before the stock steadied and reversed course Monday.

Friday's pullback marked a sharp reversal for a stock that had been trading roughly 6.73% higher in the week leading into that session, according to market data. Even with Monday's gain, Mesoblast shares remain down significantly for the year, having traded as much as 20% below their starting point in 2026 at the low point of Friday's slide.

The volatility has been a recurring theme for Mesoblast in recent months. Shares reached a four-year high of $3.37 in early January after the company secured U.S. Food and Drug Administration approval in December for its flagship cell therapy Ryoncil, known generically as........

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