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 14.86% per annum.
- COST price at the close of October 13, 2026 was $954.63 and was inside the primary price channel.
- The secondary trend is increasing.
- The growth rate of the secondary trend is 162.00% per annum.
- COST price at the close of October 13, 2026 was inside the secondary price channel.
- 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 COST 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: February 12, 2026
End date: October 7, 2026
a = 7.0288
b = -0.0004
s = 0.0265
Annual growth rate:
Exp(365 × b) – 1
= Exp(365 × -0.0004) – 1
= -14.86%
Price channel spread:
Exp(4 × s) – 1
= Exp(4 × 0.0265) – 1
= 11.19%
February 12, 2026 calculations
Top border of price channel:
Exp(Y160)
= Exp(a + b × X160 + 2 × s)
= Exp(a + b × 232 + 2 × s)
= Exp(7.0288 + -0.0004 × 232 + 2 × 0.0265)
= Exp(6.9796)
= $1,074.45
Bottom border of price channel:
Exp(Y160)
= Exp(a + b × X160 – 2 × s)
= Exp(a + b × 232 – 2 × s)
= Exp(7.0288 + -0.0004 × 232 – 2 × 0.0265)
= Exp(6.8735)
= $966.35
October 7, 2026 calculations
Top border of price channel:
Exp(Y323)
= Exp(a + b × X323 + 2 × s)
= Exp(a + b × 469 + 2 × s)
= Exp(7.0288 + -0.0004 × 469 + 2 × 0.0265)
= Exp(6.8751)
= $967.86
Bottom border of price channel:
Exp(Y323)
= Exp(a + b × X323 – 2 × s)
= Exp(a + b × 469 – 2 × s)
= Exp(7.0288 + -0.0004 × 469 – 2 × 0.0265)
= Exp(6.7690)
= $870.48
Description
- The primary trend is decreasing.
- The decline rate of the primary trend is 14.86% per annum.
- COST price at the close of October 13, 2026 was $954.63 and was inside the primary price channel.
Secondary Trend
Start date: September 16, 2026
End date: October 13, 2026
a = 5.6073
b = 0.0026
s = 0.0077
Annual growth rate:
Exp(365 × b) – 1
= Exp(365 × 0.0026) – 1
= 162.00%
Price channel spread:
Exp(4 × s) – 1
= Exp(4 × 0.0077) – 1
= 3.12%
September 16, 2026 calculations
Top border of price channel:
Exp(Y308)
= Exp(a + b × X308 + 2 × s)
= Exp(a + b × 448 + 2 × s)
= Exp(5.6073 + 0.0026 × 448 + 2 × 0.0077)
= Exp(6.8048)
= $902.21
Bottom border of price channel:
Exp(Y308)
= Exp(a + b × X308 – 2 × s)
= Exp(a + b × 448 – 2 × s)
= Exp(5.6073 + 0.0026 × 448 – 2 × 0.0077)
= Exp(6.7741)
= $874.91
October 13, 2026 calculations
Top border of price channel:
Exp(Y327)
= Exp(a + b × X327 + 2 × s)
= Exp(a + b × 475 + 2 × s)
= Exp(5.6073 + 0.0026 × 475 + 2 × 0.0077)
= Exp(6.8761)
= $968.84
Bottom border of price channel:
Exp(Y327)
= Exp(a + b × X327 – 2 × s)
= Exp(a + b × 475 – 2 × s)
= Exp(5.6073 + 0.0026 × 475 – 2 × 0.0077)
= Exp(6.8454)
= $939.52
Description
- The secondary trend is increasing.
- The growth rate of the secondary trend is 162.00% per annum.
- COST price at the close of October 13, 2026 was inside the secondary price channel.