S. INCOME TAXES

The effective tax rate for the three months ended September 27, 2026 and September 28, 2025 was 14.8% and 15.8%, respectively. The decrease in the effective tax rate from the three months ended September 28, 2025 to the three months ended September 27, 2026 is primarily attributable to a reduction in U.S. taxation of international income. This reduction was partially offset by an increase from a projected shift in the geographic distribution of income.

The effective tax rate for the nine months ended September 27, 2026 and September 28, 2025 was 14.4% and 13.8%, respectively. The increase in the effective tax rate from the nine months ended September 28, 2025 to the nine months ended September 27, 2026 is primarily attributable to lower benefits from tax credits and a projected shift in the geographic distribution of income. These increases were partially offset by a reduction related to U.S. taxation of international income.

On a quarterly basis, Teradyne evaluates the realizability of the deferred tax assets by jurisdiction and assesses the need for a valuation allowance. As of September 27, 2026, Teradyne believes that it will ultimately realize the deferred tax assets recorded on the condensed consolidated balance sheet. However, should Teradyne believe that it is more-likely-than-not that the deferred tax assets would not be realized, the tax provision would increase in the period in which Teradyne determined that the realizability was not

likely. Teradyne considers the probability of future taxable income and historical profitability, among other factors, in assessing the realizability of the deferred tax assets.

As of both September 27, 2026, and December 31, 2025, Teradyne had $6.9 million of reserves for uncertain tax positions.

Teradyne recognizes interest and penalties related to income tax matters in income tax expense. As of September 27, 2026, and December 31, 2025, $0.3 million and $0.3 million, respectively, of interest and penalties were accrued for uncertain tax positions. For the nine months ended September 27, 2026, and September 28, 2025, an expense of less than $0.1 million and less than $0.1 million, respectively, was recorded for interest and penalties related to income tax items.

Teradyne qualifies for a tax holiday in Singapore by fulfilling the requirements of an agreement with the Singapore Economic Development Board under which certain headcount and spending requirements must be met. The tax savings due to the tax holiday for the nine months ended September 27, 2026 and September 28, 2025, were $16.4 million, or $0.10 per diluted share, and $7.4 million, or $0.05 per diluted share, respectively. In December 2025, Teradyne entered into a new agreement with the Singapore Economic Development Board which extended our Singapore tax holiday under substantially similar terms to the agreement which expired on December 31, 2025. The new tax holiday is scheduled to expire on December 31, 2035.

On January 5, 2026, the Organisation for Economic Co-operation and Development (OECD/G20) Inclusive Framework released a ‘side-by-side’ arrangement that provides a safe harbor for U.S.-headquartered multinationals. The arrangement recognizes the U.S. tax system as operating alongside the Pillar Two GloBE rules for fiscal years beginning on or after January 1, 2026. Under this arrangement, Teradyne’s U.S.-parented group and its foreign subsidiaries are expected to be exempt from the Income Inclusion Rule (IIR) and the Undertaxed Profits Rule (UTPR) in jurisdictions that adopt the safe harbor. The European Union has confirmed that the safe harbor applies under the existing EU minimum tax directive, and several other jurisdictions in which Teradyne operates have enacted the safe harbor into local law. Certain other jurisdictions have proposed but not yet enacted legislation adopting the safe harbor with effect from January 1, 2026. Teradyne does not currently expect the IIR or UTPR to have a material impact on its consolidated financial statements. Teradyne continues to monitor the enactment of the side-by-side arrangement in the remaining jurisdictions and the implementation of Qualified Domestic Minimum Top-up Taxes (QDMTTs), which are unaffected by the side-by-side arrangement.