Stock Price Trends

Graham Holdings Co (GHC)

Graham Holdings Company is a diversified global media and education company. The company is headquartered in Arlington, Virginia.

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 34.57% per annum.
  • GHC price at the close of April 28, 2025 was $922.77 and was inside the primary price channel.
  • The secondary trend is increasing.
  • The growth rate of the secondary trend is 4.44% per annum.
  • GHC price at the close of April 28, 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 GHC 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: April 25, 2023
End date: April 28, 2025

a = 5.3900

b = 0.0008

s = 0.0484

Annual growth rate:

Exp(365 × b) – 1
= Exp(365 × 0.0008) – 1
= 34.57%

Price channel spread:

Exp(4 × s) – 1
= Exp(4 × 0.0484) – 1
= 21.34%

April 25, 2023 calculations

Top border of price channel:

Exp(Y752)
= Exp(a + b × X752 + 2 × s)
= Exp(a + b × 1,091 + 2 × s)
= Exp(5.3900 + 0.0008 × 1,091 + 2 × 0.0484)
= Exp(6.3742)
= $586.53

Bottom border of price channel:

Exp(Y752)
= Exp(a + b × X752 – 2 × s)
= Exp(a + b × 1,091 – 2 × s)
= Exp(5.3900 + 0.0008 × 1,091 – 2 × 0.0484)
= Exp(6.1808)
= $483.37

April 28, 2025 calculations

Top border of price channel:

Exp(Y1,255)
= Exp(a + b × X1,255 + 2 × s)
= Exp(a + b × 1,825 + 2 × s)
= Exp(5.3900 + 0.0008 × 1,825 + 2 × 0.0484)
= Exp(6.9713)
= $1,065.63

Bottom border of price channel:

Exp(Y1,255)
= Exp(a + b × X1,255 – 2 × s)
= Exp(a + b × 1,825 – 2 × s)
= Exp(5.3900 + 0.0008 × 1,825 – 2 × 0.0484)
= Exp(6.7779)
= $878.20

Description

  • The primary trend is increasing.
  • The growth rate of the primary trend is 34.57% per annum.
  • GHC price at the close of April 28, 2025 was $922.77 and was inside the primary price channel.

Secondary Trend

Start date: November 6, 2024
End date: April 28, 2025

a = 6.6206

b = 0.0001

s = 0.0339

Annual growth rate:

Exp(365 × b) – 1
= Exp(365 × 0.0001) – 1
= 4.44%

Price channel spread:

Exp(4 × s) – 1
= Exp(4 × 0.0339) – 1
= 14.54%

November 6, 2024 calculations

Top border of price channel:

Exp(Y1,139)
= Exp(a + b × X1,139 + 2 × s)
= Exp(a + b × 1,652 + 2 × s)
= Exp(6.6206 + 0.0001 × 1,652 + 2 × 0.0339)
= Exp(6.8850)
= $977.45

Bottom border of price channel:

Exp(Y1,139)
= Exp(a + b × X1,139 – 2 × s)
= Exp(a + b × 1,652 – 2 × s)
= Exp(6.6206 + 0.0001 × 1,652 – 2 × 0.0339)
= Exp(6.7492)
= $853.39

April 28, 2025 calculations

Top border of price channel:

Exp(Y1,255)
= Exp(a + b × X1,255 + 2 × s)
= Exp(a + b × 1,825 + 2 × s)
= Exp(6.6206 + 0.0001 × 1,825 + 2 × 0.0339)
= Exp(6.9055)
= $997.78

Bottom border of price channel:

Exp(Y1,255)
= Exp(a + b × X1,255 – 2 × s)
= Exp(a + b × 1,825 – 2 × s)
= Exp(6.6206 + 0.0001 × 1,825 – 2 × 0.0339)
= Exp(6.7698)
= $871.14

Description

  • The secondary trend is increasing.
  • The growth rate of the secondary trend is 4.44% per annum.
  • GHC price at the close of April 28, 2025 was inside the secondary price channel.