X0306 4 2020-02-19 0 0001561550 Datadog, Inc. DDOG 0001754862 Index Ventures VI (Jersey) LP 5TH FLOOR, 44 ESPLANADE ST. HELIER Y9 JE1 3FG JERSEY 0 0 1 0 0001638260 Index Ventures Growth III (Jersey), L.P. 5TH FLOOR, 44 ESPLANADE ST. HELIER Y9 JE1 3FG JERSEY 0 0 1 0 0001754871 Index Ventures VI Parallel Entrepreneur Fund (Jersey) LP 5TH FLOOR, 44 ESPLANADE ST. HELIER Y9 JE1 3FG JERSEY 0 0 1 0 0001591294 Yucca (Jersey) SLP 44 ESPLANADE ST. HELIER Y9 JE1 3FG JERSEY 0 0 1 0 0001785453 Index Venture Growth Associates III Ltd 5TH FLOOR, 44 ESPLANADE ST. HELIER Y9 JE1 3FG JERSEY 0 0 1 0 0001755035 Index Venture Associates VI Ltd 5TH FLOOR, 44 ESPLANADE ST. HELIER Y9 JE1 3FG JERSEY 0 0 1 0 Class A Common Stock 2020-02-19 4 S 0 215000 47.0821 D 970916 D Class A Common Stock 2020-02-20 4 J 0 970916 D 0 D Class A Common Stock 2020-02-20 4 J 0 3891573 D 1 D Class A Common Stock 2020-02-20 4 J 0 157104 D 0 D Class A Common Stock 138508 D On February 19, 2020, Index Ventures Growth III (Jersey), L.P. ("Index Growth III") sold 215,000 shares of the Issuer's Class A Common Stock. The price reported in column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $46.85 - $47.60. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. The shares are held by Index Growth III. Index Venture Growth Associates III Limited ("IVGA III") is the general partner of Index Growth III and disclaims Section 16 beneficial ownership of such shares except to the extent of its pecuniary interest therein, if any, and this report shall not be deemed an admission that such shares are beneficially owned by it for Section 16 or any other purpose. On February 20, 2020, Index Growth III distributed in-kind, without consideration, 970,916 shares of Class A Common Stock pro-rata to its limited partners, in accordance with the exemption under Rule 16a-9(a) and Rule 16a-13 of the Securities Exchange Act of 1934, as amended. On February 20, 2020, Index Ventures VI (Jersey), L.P. ("Index VI") distributed in-kind, without consideration, 3,891,573 shares of Class A Common Stock pro-rata to its partners, including its limited partners and its general partner, Index Venture Associates VI Limited ("IVA VI"), in accordance with the exemption under Rule 16a-9(a) and Rule 16a-13 of the Securities Exchange Act of 1934, as amended. On the same date, IVA VI distributed in-kind, without consideration, the 936,131 shares of Class A Common Stock received in the Index VI distribution pro-rata to its shareholders, in accordance with the exemption under Rule 16a-9(a) and Rule 16a-13 of the Securities Exchange Act of 1934, as amended. The shares are held by Index VI. IVA VI is the general partner of Index VI and disclaims Section 16 beneficial ownership of such shares except to the extent of its pecuniary interest therein, if any, and this report shall not be deemed an admission that such shares are beneficially owned by it for Section 16 or any other purpose. On February 20, 2020, Index Ventures VI Parallel Entrepreneur Fund (Jersey), L.P. ("Index VI Parallel") distributed in-kind, without consideration, 157,104 shares of Class A Common Stock pro-rata to its partners, including its limited partners and its general partner, IVA VI, in accordance with the exemption under Rule 16a-9(a) and Rule 16a-13 of the Securities Exchange Act of 1934, as amended. On the same date, IVA VI distributed in-kind, without consideration, 39,276 shares of Class A Common Stock received in the Index VI Parallel distribution pro-rata to its shareholders, in accordance with the exemption under Rule 16a-9(a) and Rule 16a-13 of the Securities Exchange Act of 1934, as amended. The shares are held by Yucca (Jersey) SLP ("Yucca"). Yucca is the administrator of the Index co-investment vehicles that are contractually required to mirror the relevant Fund's investment in the Issuer (in this case, Index Growth III, Index VI and Index VI Parallel). Each of IVGA III and IVA VI disclaims Section 16 beneficial ownership of such shares except to the extent of its pecuniary interest therein, if any, and this report shall not be deemed an admission that such shares are beneficially owned by it for Section 16 or any other purpose. Index Ventures VI (Jersey) LP, By: Index Venture Associates VI Limited, as General Partner, By: /s/ Nigel Greenwood, Its: Director 2020-02-21 Index Ventures Growth III (Jersey), LP, By: Index Venture Growth Associates III Limited, as General Partner, By: /s/ Sinead Meehan, Its: Director 2020-02-21 Index Ventures VI Parallel Entrepreneur Fund (Jersey) LP, By: Index Venture Associates VI Limited, as General Partner, By: /s/ Nigel Greenwood, Its: Director 2020-02-21 Yucca (Jersey) SLP, By Intertrust Employee Benefit Services Limited, as authorized signatory of Yucca (Jersey) SLP in its capacity as Administrator of the Index Co-Investment Scheme, By: /s/ Sarah Earles, /s/ Nick McHardy, Its: Authorized Signatories 2020-02-21 Index Venture Growth Associates III Limited, By: /s/ Sinead Meehan, Its: Director 2020-02-21 Index Venture Associates VI Limited, By: /s/ Nigel Greenwood, Its: Director 2020-02-21