X0306 4 2018-02-28 0 0001610532 Hortonworks, Inc. HDP 0001626464 Volpi Michelangelo C/O HORTONWORKS, INC. 5470 GREAT AMERICA PARKWAY SANTA CLARA CA 95054 1 0 0 0 Common Stock 10838 D Common Stock 2018-02-28 4 S 0 66674 18.18 D 1126749 I By Index Ventures V (Jersey), L.P. Common Stock 2018-02-28 4 S 0 540 18.18 D 9128 I By Index Ventures V Parallel Entrepreneur Fund (Jersey), L.P. Common Stock 2018-02-28 4 S 0 61667 18.18 D 1042132 I By Index Ventures IV (Jersey), L.P. Common Stock 2018-02-28 4 S 0 5682 18.18 D 100332 I By Index Ventures IV Parallel Entrepreneur Fund (Jersey), L.P. Common Stock 2018-02-28 4 S 0 1395 18.18 D 23578 I By Yucca (Jersey) SLP Represents the weighted average sale price for the entire number of shares sold. The sale prices range from $18.00 to $18.63 per share. The Reporting Person undertakes to provide to the staff of the SEC, the Issuer, or a stockholder of the Issuer, upon request, the number of shares sold by the Reporting Person of each separate price within the range. The Reporting Person is a partner within the Index Ventures group. Advisors within the Index Ventures group provide advice to Index Ventures IV (Jersey), L.P., Index Ventures IV Parallel Entrepreneur Fund (Jersey), L.P., Index Ventures V (Jersey), L.P., Index Ventures V Parallel Entrepreneur Fund (Jersey), L.P. and Yucca (Jersey) SLP (the "Index Funds"). The Reporting Person is involved in making recommendations to the Index Funds, but does not hold voting or dispositive power over the shares held by the Index Funds. The Reporting Person disclaims beneficial ownership of these securities, except to the extent of his pecuniary interest therein, and this report shall not be deemed an admission that the Reporting Person is the beneficial owner of such securities for Section 16 or any other purpose. /s/ David Howard as Attorney-in-Fact for Michelangelo Volpi 2018-03-02