Material Event (Form 8-K)

As previously disclosed, on February 16, 2026, Masimo Corporation, a Delaware corporation ("Masimo"), entered into an Agreement and Plan of Merger (the "Merger Agreement"), by and among Masimo, Danaher Corporation, a Delaware corporation ("Danaher"), and Mobius Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of Danaher ("Merger Sub"). Pursuant to the Merger Agreement, Merger Sub will be merged with and into Masimo (the "Merger"), with Masimo surviving the Merger as a wholly owned subsidiary of Danaher. On April 1, 2026, in connection with the Merger, Masimo filed with the Securities and Exchange Commission (the "SEC") a definitive proxy statement (as supplemented, the "Definitive Proxy Statement") with respect to the special meeting of Masimo's stockholders (the "Special Meeting") scheduled to be held virtually on May 1, 2026 at 10:00 a.m. (Pacific Time), via the internet at www.virtualshareholdermeeting.com/MASI2026SM. Additional information about how to attend the Special Meeting is contained in the Definitive Proxy Statement.

Litigation Relating to the Merger

As previously disclosed in the Definitive Proxy Statement, Masimo had received one demand letter as of April 1, 2026 challenging the adequacy of certain disclosures made in the preliminary proxy statement filed by Masimo on March 18, 2026 and demanding that Masimo and Masimo's board of directors issue supplemental disclosures before the stockholder vote on the Merger.

Following the filing of the Definitive Proxy Statement with the SEC, three complaints (the "Actions") have been filed by purported stockholders of Masimo against Masimo and members of Masimo's Board of Directors (the "Board"). The Actions are (i) Ed Smith v. Masimo Corporation et al., Index No. 652084/2026 (April 7, 2026), filed in the Supreme Court of the State of New York for the County of New York, (ii) Richard McDaniel v. Masimo Corporation et al., Index No. 65117/2026 (April 8, 2026), filed in the Supreme Court of the State of New York for the County of New York, and (iii) Donald Kendig v. Brennan et al., Case No. 26-CIV-02902 (April 10, 2026), filed in the Superior Court of the State of California for the County of San Mateo. The Actions allege, among other things, that the Definitive Proxy Statement is inaccurate or incomplete in certain respects, allegedly in violation of New York and California state law. The Actions seek, among other things, an injunction enjoining consummation of the Merger, damages and an award of attorneys' fees and expenses. In addition, Masimo also received additional demand letters from purported stockholders (collectively, the "Stockholder Letters") alleging, among other things, that the disclosures contained in the Definitive Proxy Statement are deficient and demanding that certain corrective disclosures be made.

Masimo believes that the claims in the Actions and the Stockholder Letters are without merit, that the Definitive Proxy Statement complies with applicable law and that no further disclosure is required. However, solely in order to mitigate any risk of the Actions or Stockholder Letters delaying or otherwise adversely affecting the consummation of the Merger and to minimize any costs, risks, and uncertainties inherent in any litigation related thereto, and without admitting any liability or wrongdoing, Masimo has determined to voluntarily supplement the Definitive Proxy Statement as described in this Current Report on Form 8-K. Nothing in this Current Report on Form 8-K shall be deemed an admission of the legal necessity or materiality under applicable laws of any of the disclosures set forth herein. To the contrary, Masimo specifically denies all allegations in the Actions and the Stockholder Letters and any assertion that additional disclosure was or is required. As of April 23, 2026, Masimo was not aware of the filing of other lawsuits challenging the Merger or the Definitive Proxy Statement; however, additional lawsuits arising out of the Merger or the Definitive Proxy Statement may be filed in the future. Masimo does not intend to announce the receipt or filing of each additional, or similar lawsuit.