Stock Price Trends
Stock price trends estimated using linear regression.
Summary
Key facts
- The primary trend is decreasing.
- The decline rate of the primary trend is 15.32% per annum.
- ISRG price at the close of November 4, 2026 was $482.10 and was inside the primary price channel.
- The secondary trend is increasing.
- The growth rate of the secondary trend is 243.56% per annum.
- ISRG price at the close of November 4, 2026 was higher than the top border of the secondary price channel by $2.43 (0.51%).
- The direction of the secondary trend is opposite to the direction of the primary trend. This indicates a possible reversal in the direction of the primary trend.
Linear Regression Model
Model equation:
Yi = α + β × Xi + εi
Top border of price channel:
Exp(Yi) = Exp(a + b × Xi + 2 × s)
Bottom border of price channel:
Exp(Yi) = Exp(a + b × Xi – 2 × s)
where:
i - observation number
Yi - natural logarithm of ISRG price
Xi - time index, 1 day interval
σ - standard deviation of εi
a - estimator of α
b - estimator of β
s - estimator of σ
Exp() - calculates the exponent of e
Primary Trend
Start date: October 18, 2024
End date: November 3, 2026
a = 6.8444
b = -0.0005
s = 0.0929
Annual growth rate:
Exp(365 × b) – 1
= Exp(365 × -0.0005) – 1
= -15.32%
Price channel spread:
Exp(4 × s) – 1
= Exp(4 × 0.0929) – 1
= 45.02%
October 18, 2024 calculations
Top border of price channel:
Exp(Y741)
= Exp(a + b × X741 + 2 × s)
= Exp(a + b × 1,078 + 2 × s)
= Exp(6.8444 + -0.0005 × 1,078 + 2 × 0.0929)
= Exp(6.5391)
= $691.67
Bottom border of price channel:
Exp(Y741)
= Exp(a + b × X741 – 2 × s)
= Exp(a + b × 1,078 – 2 × s)
= Exp(6.8444 + -0.0005 × 1,078 – 2 × 0.0929)
= Exp(6.1674)
= $476.95
November 3, 2026 calculations
Top border of price channel:
Exp(Y1,252)
= Exp(a + b × X1,252 + 2 × s)
= Exp(a + b × 1,824 + 2 × s)
= Exp(6.8444 + -0.0005 × 1,824 + 2 × 0.0929)
= Exp(6.1992)
= $492.37
Bottom border of price channel:
Exp(Y1,252)
= Exp(a + b × X1,252 – 2 × s)
= Exp(a + b × 1,824 – 2 × s)
= Exp(6.8444 + -0.0005 × 1,824 – 2 × 0.0929)
= Exp(5.8275)
= $339.52
Description
- The primary trend is decreasing.
- The decline rate of the primary trend is 15.32% per annum.
- ISRG price at the close of November 4, 2026 was $482.10 and was inside the primary price channel.
Secondary Trend
Start date: August 25, 2026
End date: November 4, 2026
a = -0.0493
b = 0.0034
s = 0.0257
Annual growth rate:
Exp(365 × b) – 1
= Exp(365 × 0.0034) – 1
= 243.56%
Price channel spread:
Exp(4 × s) – 1
= Exp(4 × 0.0257) – 1
= 10.83%
August 25, 2026 calculations
Top border of price channel:
Exp(Y1,203)
= Exp(a + b × X1,203 + 2 × s)
= Exp(a + b × 1,754 + 2 × s)
= Exp(-0.0493 + 0.0034 × 1,754 + 2 × 0.0257)
= Exp(5.9330)
= $377.30
Bottom border of price channel:
Exp(Y1,203)
= Exp(a + b × X1,203 – 2 × s)
= Exp(a + b × 1,754 – 2 × s)
= Exp(-0.0493 + 0.0034 × 1,754 – 2 × 0.0257)
= Exp(5.8302)
= $340.42
November 4, 2026 calculations
Top border of price channel:
Exp(Y1,253)
= Exp(a + b × X1,253 + 2 × s)
= Exp(a + b × 1,825 + 2 × s)
= Exp(-0.0493 + 0.0034 × 1,825 + 2 × 0.0257)
= Exp(6.1731)
= $479.67
Bottom border of price channel:
Exp(Y1,253)
= Exp(a + b × X1,253 – 2 × s)
= Exp(a + b × 1,825 – 2 × s)
= Exp(-0.0493 + 0.0034 × 1,825 – 2 × 0.0257)
= Exp(6.0703)
= $432.80
Description
- The secondary trend is increasing.
- The growth rate of the secondary trend is 243.56% per annum.
- ISRG price at the close of November 4, 2026 was higher than the top border of the secondary price channel by $2.43 (0.51%).