Completion of Acquisition or Disposition of Assets On August 10, 2026 (Tokyo time), Onto Innovation Inc. (the “Company”) completed the previously announced acquisition of 61,123,436 shares (27% of the issued and outstanding shares) of the common stock of Rigaku Holdings Corporation (“Rigaku”), pursuant to the Share Purchase Agreement (the “Purchase Agreement”), dated as of April 21, 2026, by and between the Company and Atom Investment, L.P. (the “Seller”), an affiliate of The Carlyle Group. A…

Results of Operations and Financial Condition. On August 6, 2026, Onto Innovation Inc. announced in a news release its results for its fiscal second quarter ended June 30, 2026 and other related material information (the “Earnings Release”). A copy of the Earnings Release is attached hereto as Exhibit 99.1 and incorporated by reference herein. The information in this Current Report on Form 8-K and the Exhibit attached hereto shall not be deemed “filed” for purposes of Section 18 of the Securi…

Other Events. On May 18, 2026, the Company issued a press release announcing the pricing of the Notes. A copy of the press release is attached hereto as Exhibit 99.1 and incorporated herein by reference. Concurrently with the offering of the Notes, the Company used $204,979,372.25 of the net proceeds from the offering to repurchase 805,325 shares of Onto Innovation Inc.’s Common Stock in privately negotiated transactions effected with or through one of the initial purchasers or one or more of…

Entry into a Material Definitive Agreement. Indenture and Notes On May 21, 2026, Onto Innovation Inc. (the “Company”) issued $1,500,000,000 aggregate principal amount of 0.00% Convertible Senior Notes due 2031 (the “Notes”). The Notes were issued pursuant to an Indenture, dated May 21, 2026 (the “Indenture”), between the Company and U.S. Bank Trust Company, National Association, as trustee (the “Trustee”). Pursuant to the purchase agreement between the Company and the representative of the in…

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. The information set forth under

Unregistered Sales of Equity Securities. The information set forth under

Other Events On May 18, 2026, Onto Innovation Inc. (the “Company”) issued a press release announcing that the Company plans to commence, subject to market conditions and other factors, a private offering (the “Offering”) of $1,100,000,000 aggregate principal amount of convertible senior notes due 2031 (the “Notes”) to persons reasonably believed to be qualified institutional buyers pursuant to Rule 144A under the Securities Act of 1933 (the “Securities Act”). A copy of the press release is at…

Results of Operations and Financial Condition. On May 5, 2026, Onto Innovation Inc. announced in a news release its results for its fiscal first quarter ended March 31, 2026 and other related material information (the “Earnings Release”). A copy of the Earnings Release is attached hereto as Exhibit 99.1 and incorporated by reference herein. The information in this Current Report on Form 8-K and the Exhibit attached hereto shall not be deemed “filed” for purposes of Section 18 of the Securitie…

Entry into a Material Definitive Agreement On April 21, 2026 (Tokyo time), Onto Innovation Inc. (the “Company”) entered into a Share Purchase Agreement (the “Purchase Agreement”), with Atom Investments, L.P. (the “Seller”), an affiliate of The Carlyle Group, pursuant to which the Company agreed to acquire 61,123,436 shares (27% of the issued and outstanding shares) of the common stock of Rigaku Holdings Corporation (“Rigaku”), from the Seller for an aggregate purchase price of approximately $…

Other Events In connection with entering into the Purchase Agreement, the Company entered into a commitment letter (the “Bridge Commitment Letter”) with Goldman Sachs Bank USA (the “Commitment Party”), which provides for a senior secured 364-day bridge term loan credit facility (the “Bridge Facility”) in an aggregate principal amount of up to $500 million, subject to the terms and conditions set forth therein. The Bridge Facility is intended to be available to the Company to finance, together…

Results of Operations and Financial Condition. On April 16, 2026, Onto Innovation Inc. issued a news release announcing a preliminary estimate of its revenue for its fiscal first quarter ended March 31, 2026 and establishing guidance for the fiscal second quarter ending June 30, 2026 (the “Press Release”). A copy of the Press Release is attached hereto as Exhibit 99.1 and incorporated by reference herein. The information in this Current Report on Form 8-K and the Exhibit attached hereto shall…

Results of Operations and Financial Condition. On February 19, 2026, Onto Innovation Inc. announced in a news release its results for its fiscal fourth quarter and full year ended January 3, 2026 and other related material information (the “Earnings Release”). A copy of the Earnings Release is attached hereto as Exhibit 99.1 and incorporated by reference herein. The information in this Current Report on Form 8-K and the Exhibit attached hereto shall not be deemed “filed” for purposes of Secti…

The filing discloses the adoption of a nonqualified deferred compensation plan, which is a compensatory arrangement rather than a change in management personnel.

Completion of Acquisition or Disposition of Assets On November 17, 2025, Onto Innovation Inc. (the “Company”) completed the previously announced acquisition of Semilab USA LLC (“Semilab USA”), pursuant to the Equity Purchase Agreement (the “Purchase Agreement”), dated as of June 27, 2025, by and among the Company, Semilab International Zrt. (the “Seller”), Semilab Zrt. and Semilab USA, as amended by the Amendment to Equity Purchase Agreement, dated October 9, 2025. As previously disclosed, pu…

Unregistered Sale of Equity Securities As described in Item 2.01, the Company issued 641,771 shares of Common Stock to the Seller pursuant to the Purchase Agreement. The issuance was exempt from registration pursuant to Section 4(a)(2) of the Securities Act of 1933, as amended (the “Securities Act”). The Seller has represented that it is an “accredited investor” as defined in Rule 501 under the Securities Act and that the Common Stock is being acquired for investment purposes and not with a v…

Results of Operations and Financial Condition. On November 6, 2025, Onto Innovation Inc. announced in a news release its results for its fiscal third quarter ended September 27, 2025 and other related material information (the “Earnings Release”). A copy of the Earnings Release is attached hereto as Exhibit 99.1 and incorporated by reference herein. The information in this Current Report on Form 8-K and the Exhibit attached hereto shall not be deemed “filed” for purposes of Section 18 of the…

Regulation FD Disclosure The EIR Business represents approximately $13 million, or 10%, of estimated 2025 revenue for Semilab USA. The Company expects that the business to be acquired, excluding the EIR Business, pursuant to the amended Transaction will generate approximately $120 million in annual revenue and will increase earnings per share by approximately 10% in the first year following the close of the transaction. Additionally, the Company affirms its third quarter guidance, initially p…

Entry into a Material Definitive Agreement As previously announced, on June 27, 2025, Onto Innovation Inc. (the “Company”) entered into an Equity Purchase Agreement (the “Purchase Agreement”) with Semilab International Zrt. (the “Seller”), Semilab Zrt. and Semilab USA LLC (“Semilab USA”), pursuant to which the Company agreed to acquire all of the outstanding membership interests of Semilab USA from the Seller (the “Transaction”), subject to the satisfaction of customary closing conditions, in…

Results of Operations and Financial Condition. On August 7, 2025, Onto Innovation Inc. announced in a news release its results for its fiscal second quarter ended June 28, 2025 and other related material information (the “Earnings Release”). A copy of the Earnings Release is attached hereto as Exhibit 99.1 and incorporated by reference herein. The information in this Current Report on Form 8-K and the Exhibit attached hereto shall not be deemed “filed” for purposes of Section 18 of the Securi…

CFO — Mark Slicer: The CFO, a principal financial officer, mutually terminated his employment, representing the loss of a key senior executive.

As described in Item 1.01, the Company has agreed to issue 706,215 shares of Common Stock to the Seller pursuant to the Purchase Agreement. The issuance will be exempt from registration pursuant to Section 4(a)(2) of the Securities Act of 1933, as amended (the “Securities Act”). The Seller has represented that it is an “accredited investor” as defined in Rule 501 under the Securities Act and that the Common Stock is being acquired for investment purposes and not with a view toward or for sale…

Entry into a Material Definitive Agreement On June 27, 2025, Onto Innovation Inc. (the “Company”) entered into an Equity Purchase Agreement (the “Purchase Agreement”), with Semilab International Zrt. (the “Seller”), Semilab Zrt. and Semilab USA LLC (“Semilab USA”), pursuant to which the Company agreed to acquire all of the outstanding membership interests of Semilab USA from the Seller for $475,000,000 in cash (subject to certain customary purchase price adjustments) and 706,215 shares of the…

CFO — Brian Roberts: The filing announces the appointment of an external candidate as the new Chief Financial Officer, which is a significant management change but not a departure of a sitting executive.

CFO — Mark Slicer: The immediate mutual termination of the sitting CFO represents a sudden loss of a key senior executive without a named successor in the filing.

Results of Operations and Financial Condition. On May 8, 2025, Onto Innovation Inc. announced in a news release its results for its fiscal first quarter ended March 29, 2025 and other related material information (the “Earnings Release”). A copy of the Earnings Release is attached hereto as Exhibit 99.1 and incorporated by reference herein. The information in this Current Report on Form 8-K and the Exhibit attached hereto shall not be deemed “filed” for purposes of Section 18 of the Securitie…