Artisan Partners Asset Management Inc. and affiliated entities filed an amended Schedule 13G with the SEC on November 12, 2026, disclosing beneficial ownership of approximately 6.7% of iRhythm Holdings, Inc. common stock as of September 30, 2026.

Key Highlights

  • Aggregate beneficial ownership: The Artisan Partners entities collectively reported beneficial ownership of 2,195,855.14 shares of iRhythm Holdings common stock.
  • Percent of class: The reported holdings represent 6.7% of the outstanding class of common stock (CUSIP 450056106).
  • Shared voting power: The reporting persons disclosed shared power to vote or direct the vote for 1,951,280.14 shares, with no sole voting power reported.
  • Shared dispositive power: All 2,195,855.14 shares are subject to shared dispositive power; sole dispositive power is reported as none.
  • Client accounts: According to the filing, the shares were acquired on behalf of discretionary clients of Artisan Partners Limited Partnership, with those clients entitled to dividends and sale proceeds.
  • Event date: The date of the event requiring this filing is stated as September 30, 2026.
  • Signing officer: Gregory K. Ramirez, Executive Vice President of Artisan Partners Asset Management Inc., signed the filing dated November 11, 2026.

Artisan Partners Entities Disclose Combined iRhythm Holdings Position

Four affiliated Artisan Partners entities - Artisan Partners Asset Management Inc. (APAM), Artisan Partners Holdings LP, Artisan Investments GP LLC, and Artisan Partners Limited Partnership (APLP) - each reported an aggregate beneficial ownership of 2,195,855.14 shares of iRhythm Holdings, Inc. common stock in this Amendment No. 1 to Schedule 13G. All four entities are incorporated or organized in Delaware and share a principal business address at 875 East Wisconsin Avenue, Suite 800, Milwaukee, WI 53202, according to the filing.

The filing describes the organizational structure as follows: Artisan Partners Holdings LP is the sole limited partner of Artisan Partners Limited Partnership and the sole member of Artisan Investments GP LLC; Artisan Investments GP LLC is the general partner of Artisan Partners Limited Partnership; and Artisan Partners Asset Management Inc. is the general partner of Artisan Partners Holdings LP. APLP is classified as an investment adviser registered under Section 203 of the Investment Advisers Act of 1940, while the remaining three entities are classified as parent holding companies or control persons.

The filing states that "the shares reported herein have been acquired on behalf of discretionary clients of APLP" and that "persons other than APLP are entitled to receive all dividends from, and proceeds from the sale of, those shares." The filing further notes that none of those persons, to the knowledge of the reporting entities, has an economic interest in more than 5% of the class. The certifying parties affirmed that the securities "were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer."

What Was Disclosed

Artisan Partners and its affiliates filed an amended Schedule 13G disclosing a combined 2,195,855.14-share beneficial ownership position in iRhythm Holdings, Inc., equal to 6.7% of the common stock class, as of September 30, 2026, held on behalf of discretionary client accounts.