X0306 4 2014-09-15 0 0001294133 Inogen Inc INGN 0001433352 ARBORETUM VENTURES II LP 303 DETROIT STREET, SUITE 301 ANN ARBOR MI 48104 0 0 1 0 0001592724 Arboretum Ventures 1, LLC 303 DETROIT STREET, SUITE 301 ANN ARBOR MI 48104 0 0 1 0 0001592721 Arboretum Investment Manager, LLC 303 DETROIT STREET, SUITE 301 ANN ARBOR MI 48104 0 0 1 0 0001592723 Arboretum Investment Manager IIa, LLC 303 DETROIT STREET, SUITE 301 ANN ARBOR MI 48104 0 0 1 0 0001592760 Arboretum Ventures 1-A, LLC 303 DETROIT STREET, SUITE 301 ANN ARBOR MI 48104 0 0 1 0 0001433353 ARBORETUM VENTURES 11A LP 303 DETROIT STREET, SUITE 301 ANN ARBOR MI 48104 0 0 1 0 0001592722 Arboretum Investment Manager II, LLC 303 DETROIT STREET, SUITE 301 ANN ARBOR MI 48104 0 0 1 0 0001592732 Garfinkle Jan L. 303 DETROIT STREET, SUITE 301 ANN ARBOR MI 48104 0 0 1 0 Common Stock 2014-09-15 4 S 0 1311 21.4505 D 299547 I see footnote Common Stock 2014-09-15 4 S 0 874 21.4505 D 199693 I see footnote Common Stock 2014-09-15 4 S 0 5928 21.4505 D 1358542 I see footnote Common Stock 2014-09-15 4 S 0 1387 21.4505 D 318301 I see footnote Common Stock 2014-09-16 4 S 0 897 21.1615 D 298650 I see footnote Common Stock 2014-09-16 4 S 0 598 21.1615 D 199095 I see footnote Common Stock 2014-09-16 4 S 0 4056 21.1615 D 1354486 I see footnote Common Stock 2014-09-16 4 S 0 949 21.1615 D 317352 I see footnote Common Stock 2014-09-17 4 S 0 5401 21.7238 D 293249 I see footnote Common Stock 2014-09-17 4 S 0 3600 21.7238 D 195495 I see footnote Common Stock 2014-09-17 4 S 0 24420 21.7238 D 1330066 I see footnote Common Stock 2014-09-17 4 S 0 5714 21.7238 D 311638 I see footnote The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on June 5, 2014. Price reflected is the weighted-average sale price for shares sold. The range of sale prices for the transactions reported was $21.00 to $22.600 per share. Each Reporting Person undertakes to provide, upon request by the SEC staff, the Issuer, or a security holder of the Issuer, full information regarding the number of shares sold at each separate price. These shares are held by Arboretum Ventures 1, LLC ("Ventures 1"). Arboretum Investment Manager, LLC ("AIM") serves as the managing member of Ventures 1. Arboretum Ventures, Inc. ("INC") serves as the Manager of AIM. Jan Garfinkle and Timothy Petersen are the sole shareholders of INC and share the power to vote or dispose of these shares and therefore may be deemed to have voting and investment power with respect to such shares; however, they disclaim beneficial ownership of the shares except to the extent of their pecuniary interests therein. Timothy Petersen is a director of the Issuer and, accordingly, files separate Section 16 reports. These shares are held by Arboretum Ventures 1-A, LLC ("Ventures 1-A"). AIM serves as the managing member of Ventures 1-A. INC serves as the Manager of AIM. Jan Garfinkle and Timothy Petersen are the sole shareholders of INC and share the power to vote or dispose of these shares and therefore may be deemed to have voting and investment power with respect to such shares; however, they disclaim beneficial ownership of the shares except to the extent of their pecuniary interests therein. Timothy Petersen is a director of the Issuer and, accordingly, files separate Section 16 reports. These shares are held by Arboretum Ventures II, L.P ("Ventures II"). Arboretum Investment Manager II, LLC ("AIM II") serves as the general partner of Ventures II. Jan Garfinkle and Timothy Petersen are the managing members of AIM II and share the power to vote or dispose of these shares and therefore may be deemed to have voting and investment power with respect to such shares; however, they disclaim beneficial ownership of the shares except to the extent of their pecuniary interests therein. Timothy Petersen is a director of the Issuer and, accordingly, files separate Section 16 reports. These shares are held by Arboretum Ventures IIa, L.P ("Ventures IIa). AIM II serves as the sole manager of Arboretum Investment Manager IIa, LLC ("AIM IIa"), which serves as the general partner of Ventures IIa. Jan Garfinkle and Timothy Petersen are the managing members of AIM II and share the power to vote or dispose of these shares and therefore may be deemed to have voting and investment power with respect to such shares; however, they disclaim beneficial ownership of the shares except to the extent of their pecuniary interests therein. Timothy Petersen is a director of the Issuer and, accordingly, files separate Section 16 reports. Price reflected is the weighted-average sale price for shares sold. The range of sale prices for the transactions reported was $21.00 to $21.350 per share. Each Reporting Person undertakes to provide, upon request by the SEC staff, the Issuer, or a security holder of the Issuer, full information regarding the number of shares sold at each separate price. Price reflected is the weighted-average sale price for shares sold. The range of sale prices for the transactions reported was $21.3450 to $22.2500 per share. Each Reporting Person undertakes to provide, upon request by the SEC staff, the Issuer, or a security holder of the Issuer, full information regarding the number of shares sold at each separate price. /s/ Marcy Marshall as attorney-in-fact 2014-09-17