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

Jan. 23, 2020 AC -4.19%
Oct. 17, 2019 AC +6.96%
July 18, 2019 AC -1.45%
April 18, 2019 AC -7.00% Biggest DOWN
Jan. 24, 2019 AC -3.93%
Oct. 18, 2018 AC -3.45%
July 19, 2018 AC -0.86%
April 17, 2018 AC +8.17% Biggest UP
Jan. 25, 2018 AC -2.12%
Oct. 19, 2017 AC +3.39%
July 20, 2017 AC -4.55%
April 18, 2017 AC +6.36%

Avg (+ or -) 4.37%
Bias -0.22%, small negative bias on earnings.

With stock at 510.00 the data suggests these ranges:
Based on current IV (expected move into Friday per TOS): 484.03 to 535.97 (+/- 5.1%)
Based on AVERAGE one-day move over last 12 quarters: 487.28 to 532.28
Based on MAXIMUM one-day move over last 12 Q’s (8.2%): 468.33 to 551.67
Based on DOWN max only (-7.0%): 474.30

Open to requests for other symbols.