Editas Medicine, Inc. — Director's Dealing 2016

Dec 7, 2016

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: Editas Medicine, Inc. (EDIT)
CIK: 0001650664
Period of Report: 2016-12-05

Reporting Person: Polaris Venture Management Co. VI, L.L.C. (10% Owner)
Reporting Person: Polaris Venture Partners VI, L.P. (10% Owner)
Reporting Person: Polaris Venture Partners Founders' Fund VI, L.P. (10% Owner)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2016-12-05	Common Stock	S	80000	$15.74	Disposed	3922144	Indirect
2016-12-06	Common Stock	S	50000	$15.87	Disposed	3872144	Indirect

Footnotes

F1: Represents 75,583 shares disposed of by Polaris Venture Partners VI, L.P. ("PVP VI") and 4,417 shares disposed of by Polaris Venture Partners Founders' Fund VI, L.P ("PVPFF VI").

F2: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $15.70 to $15.96, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnotes (2) and (5) to this Form 4.

F3: 3,705,602 of these shares are owned directly by PVP VI and 216,542 of the shares are owned by PVPFF VI (together with PVP VI, the "Polaris Funds"). Polaris Venture Management Co. VI, L.L.C. ("Polaris Management") is the general partner of each of the Polaris Funds. Kevin Bitterman, a member of the Board of Directors of the Issuer, has an assignee interest in Polaris Management. Each of Polaris Management and Mr. Bitterman disclaim beneficial ownership of all the shares owned by the Polaris Funds and this report shall not be deemed an admission that either is the beneficial owner of such shares for purposes of Section 16 or for any other purpose, except to the extent of their pecuniary interests therein.

F4: Represents 47,240 shares disposed of by PVP VI and 2,760 shares disposed of by PVPFF VI.

F5: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $15.80 to $15.94, inclusive.

F6: 3,658,362 of these shares are owned directly by PVP VI and 213,782 of the shares are owned by PVPFF VI . Each of Polaris Management and Mr. Bitterman disclaim beneficial ownership of all the shares owned by the Polaris Funds and this report shall not be deemed an admission that either is the beneficial owner of such shares for purposes of Section 16 or for any other purpose, except to the extent of their pecuniary interests therein.