Stock Markets April 21, 2026 12:29 AM

Rigaku Shares Rally to Record as Onto Innovation Agrees to Major Stake Purchase and Strategic Alliance

Tokyo-listed Rigaku jumps after Onto plan to buy roughly 27% stake from existing shareholder and deepen hybrid metrology cooperation

By Ajmal Hussain ONTO
Rigaku Shares Rally to Record as Onto Innovation Agrees to Major Stake Purchase and Strategic Alliance
ONTO

Rigaku Holdings shares climbed to an all-time high after Onto Innovation announced a planned acquisition of about 61.1 million shares, or 27% of Rigaku's outstanding stock, from Atom Investment in the second half of 2026, subject to regulatory approvals. The deal, which will make Onto the largest shareholder, complements a collaboration begun in 2025 to develop hybrid metrology solutions combining Rigaku's X-ray systems with Onto's optical and analytics capabilities. Rigaku said the tie-up should have limited near-term earnings impact but is expected to support medium- to long-term growth and corporate value through technology and customer synergies.

Key Points

  • Onto Innovation plans to acquire about 61.1 million Rigaku shares (27% of outstanding stock) from Atom Investment in H2 2026, pending regulatory approvals.
  • The transaction will make Onto the largest shareholder in Rigaku, replacing Atom.
  • The alliance builds on a 2025 collaboration to develop hybrid metrology solutions that combine Rigaku's X-ray technologies with Onto's optical systems and analytics; Rigaku expects limited near-term earnings impact but anticipates medium- to long-term growth and corporate value gains.

Rigaku Holdings saw its shares surge to record levels after an announcement that Onto Innovation intends to acquire a significant equity stake and expand a strategic business alliance focused on semiconductor metrology.

The proposed share purchase involves Onto buying approximately 61.1 million Rigaku shares, representing 27% of outstanding stock, from existing shareholder Atom Investment. The transaction is scheduled for the second half of 2026 and is subject to regulatory approvals. If completed, Onto will replace Atom as Rigaku's largest shareholder.

In response to the news, Rigaku's Tokyo-listed stock jumped 22.1% to 2,766.0 yen, marking its highest closing level on record. Market participants reacted strongly to the combination of fresh capital and an expanded cooperative arrangement between the two firms.

The equity move builds on a collaboration launched in 2025 to create hybrid metrology solutions that pair Rigaku's X-ray technologies with Onto Innovation's optical measurement systems and analytics. The companies described the cooperation as a way to combine complementary technology stacks to address growing complexity in semiconductor manufacturing.

Rigaku emphasized that demand for more sophisticated process control tools is increasing as chip production faces finer geometries and multi-layer designs. The company framed the alliance as a response to that technical trend, highlighting product and customer synergies as the rationale for the deeper relationship.

On the financial side, Rigaku stated the alliance is expected to have only a limited impact on near-term earnings. However, management anticipates the partnership will help support medium- to long-term revenue growth and enhance corporate value through integrated technology development and cross-selling opportunities.


Context and implications

  • The transaction would reposition ownership by making Onto Innovation the largest holder of Rigaku stock, replacing Atom Investment.
  • The technical partnership leverages Rigaku's X-ray measurement expertise and Onto's optical and analytics capabilities to pursue hybrid metrology solutions.
  • Rigaku expects limited immediate earnings effects but forecasts longer-term growth benefits from combined technology and customer synergies.

Sectors affected

  • Semiconductor equipment and metrology - direct impact through product development and customer offerings.
  • Capital markets - notable move in shareholder composition and a material stock-price reaction.
  • Industrial technology - potential medium- to long-term effects on suppliers and systems integrators serving chip manufacturers.

Risks

  • Regulatory approval risk - the planned acquisition is subject to regulatory clearances that could delay or prevent the transaction, affecting ownership and strategic plans. This impacts capital markets and corporate governance.
  • Near-term earnings uncertainty - Rigaku expects limited impact on near-term earnings, indicating potential short-term financial stagnation despite strategic benefits. This affects investors and financial markets monitoring near-term performance.
  • Execution risk on technology and customer synergies - realizing medium- to long-term growth depends on successful integration of X-ray and optical analytics offerings, which impacts the semiconductor equipment and industrial technology sectors.

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