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

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%
Jan. 24, 2017 AC +5.09%
Oct. 18, 2016 AC -5.56%

Avg (+ or -) 4.33%
Bias -0.49%, slight negative bias on earnings.

With stock at 535.00 the data suggests these ranges:
Based on current IV (expected move into Friday per TOS): 512.55 to 557.45
Based on AVERAGE one-day move over last 12 quarters: 511.85 to 558.15
Based on MAXIMUM one-day move over last 12 Q’s (8.2%): 491.29 to 578.71
Based on DOWN max only (-7.0%): 497.55

Open to requests for other symbols.