X0306 4 2018-03-08 0 0001388658 iRhythm Technologies, Inc. IRTC 0001340806 Lathi Vijay K C/O NEW LEAF VENTURES 7 TIMES SQUARE, SUITE 3502 NEW YORK NY 10036 1 0 0 0 Common Stock 2018-03-08 4 S 0 26979 66.5004 D 87039 I See Footnote Common Stock 2018-03-08 4 S 0 2659 67.1704 D 84380 I See Footnote Common Stock 2018-03-09 4 S 0 84380 66.3969 D 0 I See Footnote Common Stock 1405 D The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $66.00 to $66.93, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission ("SEC"), upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (1) to this Form 4. Represents shares directly beneficially owned by New Leaf Ventures II, L.P. ("NLV II"). The Reporting Person is a member of New Leaf Venture Management II, L.L.C. ("Management II"). Management II is the sole general partner of New Leaf Venture Associates II, L.P. ("Associates II"). Associates II is the sole general partner of NLV II. As such, the Reporting Person shares voting and dispositive control with respect to the shares held by NLV II. The Reporting Person disclaims beneficial ownership of the shares held by NLV II, except to the extent of his proportionate pecuniary interest therein. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $67.00 to $67.33, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the SEC, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (3) to this Form 4. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $66.00 to $66.93, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the SEC, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (4) to this Form 4. The reported securities are represented by restricted stock units ("RSUs"), which represent a contingent right to receive shares of the Issuer's common stock. The RSUs fully vest on April 26, 2018. /s/ Craig L. Slutzkin, as Attorney-in-Fact for Vijay K. Lathi 2018-03-12