#Earnings $WDC reports tonight. Below are details on earnings one-day moves over the last 12 quarters.

Oct. 25, 2018 AC -18.18% Biggest DOWN
July 26, 2018 AC -7.73%
April 26, 2018 AC -7.99%
Jan. 25, 2018 AC +1.82%
Oct. 26, 2017 AC -2.53%
July 27, 2017 AC -7.54%
April 27, 2017 AC +3.92%
Jan. 25, 2017 AC -1.93%
Oct. 26, 2016 AC +5.41% Biggest UP
July 28, 2016 AC -11.52%
April 28, 2016 AC -11.28%
Jan. 28, 2016 AC +5.01%

Avg (+ or -) 7.07%
Bias -4.38%, significant negative bias on earnings.

With stock at 40.00 the data suggests these ranges:
Based on current IV (expected move into Friday per TOS): 36.81 to 43.19
Based on AVERAGE move over last 12 quarters: 37.17 to 42.83
Based on MAXIMUM move over last 12 Q’s (18.2%): 32.73 to 47.27

Open for requests on other symbols.