EDITAS MEDICINE INC

Ticker: EDIT CUSIP: 28106W103 Class: Stock

EcoR1 Capital, LLC's Holding History (CIK: 0001587114)

Note: Option positions (PUT/CALL) are excluded.

Q2 2017

Shares 717,107 Value ($000) $12,033 Avg Close $18.02 Range $13.12 - $22.74

Q4 2016

Shares 626,762 Value ($000) $10,172 Avg Close $15.18 Range $12.43 - $18.94

Q2 2016

Shares 85,469 Value ($000) $2,085 Avg Close $33.73 Range $22.50 - $43.50

Q1 2016

Shares 87,921 Value ($000) $3,037 Avg Close $26.29 Range $12.57 - $43.99

Period	Shares	Value ($000)	Average Close	Price Range
Q2 2017	717,107	$12,033	$18.02	$13.12 - $22.74
Q4 2016	626,762	$10,172	$15.18	$12.43 - $18.94
Q2 2016	85,469	$2,085	$33.73	$22.50 - $43.50
Q1 2016	87,921	$3,037	$26.29	$12.57 - $43.99