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

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% Biggest DOWN
July 19, 2016 AC +4.63%
April 19, 2016 AC +3.34%

Avg (+ or -) 4.29%
Bias 0.88%, slight positive bias on earnings.

With stock at 530.00 the data suggests these ranges:
Based on current IV (expected move into NEXT Friday per TOS): 497.67 to 562.33 (8 days, Friday)
Based on AVERAGE move over last 12 quarters: 507.28 to 552.72 (4 days, Monday)
Based on MAXIMUM move over last 12 Q’s (8.2%): 486.70 to 573.30 (4 days, Monday)
EIGHT-day max moves: UP: +9.8% (581.94), DOWN: -7.8% (488.66)

Open to requests for other symbols.