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 44.62% per annum.
- ISRG price at the close of June 18, 2026 was $406.78 and was inside the primary price channel.
- The secondary trend is decreasing.
- The decline rate of the secondary trend is 61.75% per annum.
- ISRG price at the close of June 18, 2026 was inside the secondary price channel.
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: November 10, 2025
End date: June 18, 2026
a = 8.9764
b = -0.0016
s = 0.0331
Annual growth rate:
Exp(365 × b) – 1
= Exp(365 × -0.0016) – 1
= -44.62%
Price channel spread:
Exp(4 × s) – 1
= Exp(4 × 0.0331) – 1
= 14.14%
November 10, 2025 calculations
Top border of price channel:
Exp(Y1,103)
= Exp(a + b × X1,103 + 2 × s)
= Exp(a + b × 1,603 + 2 × s)
= Exp(8.9764 + -0.0016 × 1,603 + 2 × 0.0331)
= Exp(6.4473)
= $631.00
Bottom border of price channel:
Exp(Y1,103)
= Exp(a + b × X1,103 – 2 × s)
= Exp(a + b × 1,603 – 2 × s)
= Exp(8.9764 + -0.0016 × 1,603 – 2 × 0.0331)
= Exp(6.3151)
= $552.84
June 18, 2026 calculations
Top border of price channel:
Exp(Y1,254)
= Exp(a + b × X1,254 + 2 × s)
= Exp(a + b × 1,823 + 2 × s)
= Exp(8.9764 + -0.0016 × 1,823 + 2 × 0.0331)
= Exp(6.0911)
= $441.92
Bottom border of price channel:
Exp(Y1,254)
= Exp(a + b × X1,254 – 2 × s)
= Exp(a + b × 1,823 – 2 × s)
= Exp(8.9764 + -0.0016 × 1,823 – 2 × 0.0331)
= Exp(5.9589)
= $387.18
Description
- The primary trend is decreasing.
- The decline rate of the primary trend is 44.62% per annum.
- ISRG price at the close of June 18, 2026 was $406.78 and was inside the primary price channel.
Secondary Trend
Start date: April 22, 2026
End date: June 18, 2026
a = 10.7989
b = -0.0026
s = 0.0227
Annual growth rate:
Exp(365 × b) – 1
= Exp(365 × -0.0026) – 1
= -61.75%
Price channel spread:
Exp(4 × s) – 1
= Exp(4 × 0.0227) – 1
= 9.52%
April 22, 2026 calculations
Top border of price channel:
Exp(Y1,214)
= Exp(a + b × X1,214 + 2 × s)
= Exp(a + b × 1,766 + 2 × s)
= Exp(10.7989 + -0.0026 × 1,766 + 2 × 0.0227)
= Exp(6.1952)
= $490.39
Bottom border of price channel:
Exp(Y1,214)
= Exp(a + b × X1,214 – 2 × s)
= Exp(a + b × 1,766 – 2 × s)
= Exp(10.7989 + -0.0026 × 1,766 – 2 × 0.0227)
= Exp(6.1043)
= $447.76
June 18, 2026 calculations
Top border of price channel:
Exp(Y1,254)
= Exp(a + b × X1,254 + 2 × s)
= Exp(a + b × 1,823 + 2 × s)
= Exp(10.7989 + -0.0026 × 1,823 + 2 × 0.0227)
= Exp(6.0451)
= $422.06
Bottom border of price channel:
Exp(Y1,254)
= Exp(a + b × X1,254 – 2 × s)
= Exp(a + b × 1,823 – 2 × s)
= Exp(10.7989 + -0.0026 × 1,823 – 2 × 0.0227)
= Exp(5.9542)
= $385.37
Description
- The secondary trend is decreasing.
- The decline rate of the secondary trend is 61.75% per annum.
- ISRG price at the close of June 18, 2026 was inside the secondary price channel.