iRhythm Holdings, Inc.

Rule 10b5-1 Trading Plans

During the three months ended December 31, 2025, the following Section 16 officers and directors adopted, modified, or terminated a “Rule 10b5-1 trading arrangement” (as defined in Item 408 of Regulation S-K of the Exchange Act) intended to satisfy the affirmative defense of Rule 10b5- 1(c):

(1) Each trading arrangement permitted or permits transactions through and including the date listed in the table.

(2)The aggregate number of shares of common stock that will be available for sale under the Rule 10b5-1 Plan is not yet determinable because the shares available will be net of shares sold to satisfy tax withholding obligations that arise in connection with the vesting and settlement of certain restricted stock unit and performance stock unit awards subject to the Rule 10b5-1 Plan. As such, for purposes of this disclosure, the aggregate number of shares of common stock available for sale includes 55,378 shares, assuming certain escalating minimum threshold prices specified in the Role 10b5-1 Plan are met, which reflects the aggregate maximum number of shares underlying such awards without excluding the shares that will be sold to satisfy the tax withholding obligations.

(3)The aggregate number of shares of common stock that will be available for sale under the Rule 10b5-1 Plan is not yet determinable because the shares available will be net of shares sold to satisfy tax withholding obligations that arise in connection with the vesting and settlement of certain restricted stock unit and performance stock unit awards subject to the Rule 10b5-1 Plan. As such, for purposes of this disclosure, the aggregate number of shares of common stock available for sale includes 15,799 shares, assuming certain escalating minimum threshold prices specified in the Role 10b5-1 Plan are met, which reflects the aggregate maximum number of shares underlying such awards without excluding the shares that will be sold to satisfy the tax withholding obligations.

Each of the Rule 10b5-1 trading arrangements disclosed in the above table was made in accordance with our insider trading policy, which requires a 90-day cooling off period before any transactions under the plan can be executed. Transactions made pursuant to such trading arrangements will be disclosed publicly in Section 16 filings with the SEC in accordance with applicable securities laws, rules and regulations.

During the three months ended December 31, 2025, except as set forth above, none of our Section 16 officers or directors adopted, modified, or terminated a “non-Rule 10b5-1 trading arrangement” (as defined in Item 408 of Regulation S-K of the Exchange Act).