Stock Price Trends

Group 1 Automotive Inc (GPI)

Group 1 Automotive, Inc., operates in the automotive retail industry. The company is headquartered in Houston, Texas.

Stock Price Trends

Stock price trends estimated using linear regression.

Key facts

  • The primary trend is increasing.
  • The growth rate of the primary trend is 44.80% per annum.
  • GPI price at the close of August 13, 2025 was $459.54 and was inside the primary price channel.
  • The secondary trend is increasing.
  • The growth rate of the secondary trend is 1.84% per annum.
  • GPI price at the close of August 13, 2025 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 GPI 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: June 16, 2022
End date: March 12, 2025

a = 4.3757

b = 0.0010

s = 0.0760

Annual growth rate:

Exp(365 × b) – 1
= Exp(365 × 0.0010) – 1
= 44.80%

Price channel spread:

Exp(4 × s) – 1
= Exp(4 × 0.0760) – 1
= 35.52%

June 16, 2022 calculations

Top border of price channel:

Exp(Y463)
= Exp(a + b × X463 + 2 × s)
= Exp(a + b × 671 + 2 × s)
= Exp(4.3757 + 0.0010 × 671 + 2 × 0.0760)
= Exp(5.2082)
= $182.76

Bottom border of price channel:

Exp(Y463)
= Exp(a + b × X463 – 2 × s)
= Exp(a + b × 671 – 2 × s)
= Exp(4.3757 + 0.0010 × 671 – 2 × 0.0760)
= Exp(4.9043)
= $134.86

March 12, 2025 calculations

Top border of price channel:

Exp(Y1,148)
= Exp(a + b × X1,148 + 2 × s)
= Exp(a + b × 1,671 + 2 × s)
= Exp(4.3757 + 0.0010 × 1,671 + 2 × 0.0760)
= Exp(6.2224)
= $503.90

Bottom border of price channel:

Exp(Y1,148)
= Exp(a + b × X1,148 – 2 × s)
= Exp(a + b × 1,671 – 2 × s)
= Exp(4.3757 + 0.0010 × 1,671 – 2 × 0.0760)
= Exp(5.9185)
= $371.84

Description

  • The primary trend is increasing.
  • The growth rate of the primary trend is 44.80% per annum.
  • GPI price at the close of August 13, 2025 was $459.54 and was inside the primary price channel.

Secondary Trend

Start date: November 6, 2024
End date: August 12, 2025

a = 5.9721

b = 0.0000

s = 0.0556

Annual growth rate:

Exp(365 × b) – 1
= Exp(365 × 0.0000) – 1
= 1.84%

Price channel spread:

Exp(4 × s) – 1
= Exp(4 × 0.0556) – 1
= 24.92%

November 6, 2024 calculations

Top border of price channel:

Exp(Y1,064)
= Exp(a + b × X1,064 + 2 × s)
= Exp(a + b × 1,545 + 2 × s)
= Exp(5.9721 + 0.0000 × 1,545 + 2 × 0.0556)
= Exp(6.1604)
= $473.60

Bottom border of price channel:

Exp(Y1,064)
= Exp(a + b × X1,064 – 2 × s)
= Exp(a + b × 1,545 – 2 × s)
= Exp(5.9721 + 0.0000 × 1,545 – 2 × 0.0556)
= Exp(5.9379)
= $379.12

August 12, 2025 calculations

Top border of price channel:

Exp(Y1,253)
= Exp(a + b × X1,253 + 2 × s)
= Exp(a + b × 1,824 + 2 × s)
= Exp(5.9721 + 0.0000 × 1,824 + 2 × 0.0556)
= Exp(6.1743)
= $480.23

Bottom border of price channel:

Exp(Y1,253)
= Exp(a + b × X1,253 – 2 × s)
= Exp(a + b × 1,824 – 2 × s)
= Exp(5.9721 + 0.0000 × 1,824 – 2 × 0.0556)
= Exp(5.9518)
= $384.43

Description

  • The secondary trend is increasing.
  • The growth rate of the secondary trend is 1.84% per annum.
  • GPI price at the close of August 13, 2025 was inside the secondary price channel.