#Earnings $BIIB reports tomorrow morning. Below are details on earnings one-day moves over the last 12 quarters.

July 23, 2019 BO +4.90% Biggest UP
April 24, 2019 BO -2.52%
Jan. 29, 2019 BO +1.35%
Oct. 23, 2018 BO +0.19%
July 24, 2018 BO +4.10%
April 24, 2018 BO +1.09%
Jan. 25, 2018 BO +2.08%
Oct. 24, 2017 BO -3.90% Biggest DOWN
July 25, 2017 BO -0.61%
April 25, 2017 BO +3.62%
Jan. 26, 2017 BO +2.06%
Oct. 26, 2016 AC -1.87%

Avg (+ or -) 2.36%
Bias 0.87%, positive bias on earnings.

With stock at 225.00 the data suggests these ranges:
Based on current IV (expected move into Friday per TOS): 212.84 to 237.16
Based on AVERAGE one-day move over last 12 quarters: 219.70 to 230.30
Based on MAXIMUM one-day move over last 12 Q’s (4.9%): 213.98 to 236.03
Based on DOWN max only (-3.9%): 216.23

Open to requests for other symbols.