X0306 4 2015-06-24 0 0001492674 T2 Biosystems, Inc. TTOO 0001439590 Polaris Venture Partners V, L.P. 1000 WINTER STREET, SUITE 3350 WALTHAM MA 02451 0 0 1 0 0001439586 Polaris Venture Partners Special Founders' Fund V, L.P. 1000 WINTER STREET, SUITE 3350 WALTHAM MA 02451 0 0 1 0 0001439587 Polaris Venture Partners Entrepreneurs' Fund V, L.P. 1000 WINTER STREET, SUITE 3350 WALTHAM MA 02451 0 0 1 0 0001439588 Polaris Venture Partners Founders' Fund V, L.P. 1000 WINTER STREET, SUITE 3350 WALTHAM MA 02451 0 0 1 0 0001439589 Polaris Venture Management Co. V, L.L.C. 1000 WINTER STREET, SUITE 3350 WALTHAM MA 02451 0 0 1 0 Common Stock 2015-06-24 4 S 0 282 17.6129 D 43811 I See Footnotes Common Stock 2015-06-24 4 S 0 99 17.6129 D 60055 I See Footnotes Common Stock 2015-06-24 4 S 0 144 17.6129 D 82832 I See Footnotes Common Stock 2015-06-24 4 S 0 14474 17.6129 D 2331149 I See Footnotes Common Stock 2015-06-25 4 S 0 282 16.8531 D 43529 I See Footnotes Common Stock 2015-06-25 4 S 0 99 16.8531 D 59956 I See Footnotes Common Stock 2015-06-25 4 S 0 144 16.8531 D 82688 I See Footnotes Common Stock 2015-06-25 4 S 0 14474 16.8531 D 2316675 I See Footnotes Common Stock 2015-06-26 4 S 0 282 16.7607 D 43247 I See Footnotes Common Stock 2015-06-26 4 S 0 99 16.7607 D 59857 I See Footnotes Common Stock 2015-06-26 4 S 0 144 16.7607 D 82544 I See Footnotes Common Stock 2015-06-26 4 S 0 14474 16.7607 D 2302201 I See Footnotes The transactions reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting persons on May 22, 2015. By Polaris Venture Partners Entrepreneurs' Fund V, L.P. By Polaris Venture Partners Founders' Fund V, L.P. By Polaris Venture Partners Special Founders' Fund V, L.P. By Polaris Venture Partners V, L.P. The price reported is a weighted average price. These shares were sold in multiple transactions at per share prices ranging from $17.07 to $18.25. The reporting persons undertake to provide upon request to the SEC staff, the Issuer, or any stockholder of the Issuer, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. Each of Polaris Venture Partners V, L.P., Polaris Venture Partners Special Founder's Fund V, L.P., Polaris Venture Partners Founders' Fund V, L.P. and Polaris Venture Partners Entrepreneurs' Fund V, L.P. (collectively, the "Funds") has the sole voting and investment power with respect to the shares directly held by it. The general partner of each of the Funds is Polaris Venture Management Co. V, LLC, or Polaris Management. Polaris Management may be deemed to have sole voting and investment power with respect to the shares held by the Funds and disclaims beneficial ownership of all the shares held by the Funds except to the extent of its proportionate pecuniary interest therein. The members of North Star Venture Management 2000, LLC, Terrence McGuire and Jonathan Flint, collectively the Management Members, are also members of Polaris Management, and as members of the general partner, they may be deemed to share voting and investment power over the shares held by the Funds. The Management Members disclaim beneficial ownership of such shares, except to the extent of their proportionate pecuniary interest therein. The price reported is a weighted average price. These shares were sold in multiple transactions at per share prices ranging from $16.50 to $17.37. The reporting persons undertake to provide upon request to the SEC staff, the Issuer, or any stockholder of the Issuer, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. The price reported is a weighted average price. These shares were sold in multiple transactions at per share prices ranging from $16.54 to $17.06. The reporting persons undertake to provide upon request to the SEC staff, the Issuer, or any stockholder of the Issuer, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. POLARIS VENTURE PARTNERS V, L.P. By: /s/ John J. Gannon, Attorney-in-fact 2015-06-26 POLARIS VENTURE PARTNERS SPECIAL FOUNDERS' FUND V, L.P. By: /s/ John J. Gannon, Attorney-in-fact 2015-06-26 POLARIS VENTURE PARTNERS FOUNDERS' FUND V, L.P. By: /s/ John J. Gannon, Attorney-in-fact 2015-06-26 POLARIS VENTURE PARTNERS ENTREPRENEURS' FUND V, L.P. By: /s/ John J. Gannon, Attorney-in-fact 2015-06-26 POLARIS VENTURE MANAGEMENT CO. V, LLC By: /s/ John J. Gannon, Attorney-in-fact 2015-06-26