Stock Price Trends
Stock price trends estimated using linear regression.
Summary
Key facts
- The primary trend is increasing.
- The growth rate of the primary trend is 42.57% per annum.
- COST price at the close of May 4, 2026 was $1,012.79 and was inside the primary price channel.
- The secondary trend is increasing.
- The growth rate of the secondary trend is 5.79% per annum.
- COST price at the close of May 4, 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 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: November 17, 2025
End date: May 4, 2026
a = 6.5548
b = 0.0010
s = 0.0317
Annual growth rate:
Exp(365 × b) – 1
= Exp(365 × 0.0010) – 1
= 42.57%
Price channel spread:
Exp(4 × s) – 1
= Exp(4 × 0.0317) – 1
= 13.54%
November 17, 2025 calculations
Top border of price channel:
Exp(Y158)
= Exp(a + b × X158 + 2 × s)
= Exp(a + b × 229 + 2 × s)
= Exp(6.5548 + 0.0010 × 229 + 2 × 0.0317)
= Exp(6.8408)
= $935.25
Bottom border of price channel:
Exp(Y158)
= Exp(a + b × X158 – 2 × s)
= Exp(a + b × 229 – 2 × s)
= Exp(6.5548 + 0.0010 × 229 – 2 × 0.0317)
= Exp(6.7139)
= $823.74
May 4, 2026 calculations
Top border of price channel:
Exp(Y272)
= Exp(a + b × X272 + 2 × s)
= Exp(a + b × 397 + 2 × s)
= Exp(6.5548 + 0.0010 × 397 + 2 × 0.0317)
= Exp(7.0041)
= $1,101.09
Bottom border of price channel:
Exp(Y272)
= Exp(a + b × X272 – 2 × s)
= Exp(a + b × 397 – 2 × s)
= Exp(6.5548 + 0.0010 × 397 – 2 × 0.0317)
= Exp(6.8771)
= $969.80
Description
- The primary trend is increasing.
- The growth rate of the primary trend is 42.57% per annum.
- COST price at the close of May 4, 2026 was $1,012.79 and was inside the primary price channel.
Secondary Trend
Start date: February 3, 2026
End date: May 4, 2026
a = 6.8482
b = 0.0002
s = 0.0144
Annual growth rate:
Exp(365 × b) – 1
= Exp(365 × 0.0002) – 1
= 5.79%
Price channel spread:
Exp(4 × s) – 1
= Exp(4 × 0.0144) – 1
= 5.94%
February 3, 2026 calculations
Top border of price channel:
Exp(Y210)
= Exp(a + b × X210 + 2 × s)
= Exp(a + b × 307 + 2 × s)
= Exp(6.8482 + 0.0002 × 307 + 2 × 0.0144)
= Exp(6.9244)
= $1,016.80
Bottom border of price channel:
Exp(Y210)
= Exp(a + b × X210 – 2 × s)
= Exp(a + b × 307 – 2 × s)
= Exp(6.8482 + 0.0002 × 307 – 2 × 0.0144)
= Exp(6.8668)
= $959.83
May 4, 2026 calculations
Top border of price channel:
Exp(Y272)
= Exp(a + b × X272 + 2 × s)
= Exp(a + b × 397 + 2 × s)
= Exp(6.8482 + 0.0002 × 397 + 2 × 0.0144)
= Exp(6.9383)
= $1,031.02
Bottom border of price channel:
Exp(Y272)
= Exp(a + b × X272 – 2 × s)
= Exp(a + b × 397 – 2 × s)
= Exp(6.8482 + 0.0002 × 397 – 2 × 0.0144)
= Exp(6.8806)
= $973.26
Description
- The secondary trend is increasing.
- The growth rate of the secondary trend is 5.79% per annum.
- COST price at the close of May 4, 2026 was inside the secondary price channel.