Duolingo Inc (DUOL)
None
Stock Price Trends
Stock price trends estimated using linear regression.
Key facts
- The primary trend is decreasing.
- The decline rate of the primary trend is 84.15% per annum.
- DUOL price at the close of December 10, 2025 was $197.44 and was inside the primary price channel.
- The secondary trend is increasing.
- The growth rate of the secondary trend is 1,834.95% per annum.
- DUOL price at the close of December 10, 2025 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 DUOL 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: May 2, 2025
End date: September 19, 2025
a = 13.2650
b = -0.0050
s = 0.0574
Annual growth rate:
Exp(365 × b) – 1
= Exp(365 × -0.0050) – 1
= -84.15%
Price channel spread:
Exp(4 × s) – 1
= Exp(4 × 0.0574) – 1
= 25.81%
May 2, 2025 calculations
Top border of price channel:
Exp(Y945)
= Exp(a + b × X945 + 2 × s)
= Exp(a + b × 1,374 + 2 × s)
= Exp(13.2650 + -0.0050 × 1,374 + 2 × 0.0574)
= Exp(6.4451)
= $629.62
Bottom border of price channel:
Exp(Y945)
= Exp(a + b × X945 – 2 × s)
= Exp(a + b × 1,374 – 2 × s)
= Exp(13.2650 + -0.0050 × 1,374 – 2 × 0.0574)
= Exp(6.2155)
= $500.47
September 19, 2025 calculations
Top border of price channel:
Exp(Y1,041)
= Exp(a + b × X1,041 + 2 × s)
= Exp(a + b × 1,514 + 2 × s)
= Exp(13.2650 + -0.0050 × 1,514 + 2 × 0.0574)
= Exp(5.7385)
= $310.61
Bottom border of price channel:
Exp(Y1,041)
= Exp(a + b × X1,041 – 2 × s)
= Exp(a + b × 1,514 – 2 × s)
= Exp(13.2650 + -0.0050 × 1,514 – 2 × 0.0574)
= Exp(5.5090)
= $246.89
Description
- The primary trend is decreasing.
- The decline rate of the primary trend is 84.15% per annum.
- DUOL price at the close of December 10, 2025 was $197.44 and was inside the primary price channel.
Secondary Trend
Start date: November 18, 2025
End date: December 10, 2025
a = -7.6416
b = 0.0081
s = 0.0328
Annual growth rate:
Exp(365 × b) – 1
= Exp(365 × 0.0081) – 1
= 1,834.95%
Price channel spread:
Exp(4 × s) – 1
= Exp(4 × 0.0328) – 1
= 14.01%
November 18, 2025 calculations
Top border of price channel:
Exp(Y1,083)
= Exp(a + b × X1,083 + 2 × s)
= Exp(a + b × 1,574 + 2 × s)
= Exp(-7.6416 + 0.0081 × 1,574 + 2 × 0.0328)
= Exp(5.2000)
= $181.27
Bottom border of price channel:
Exp(Y1,083)
= Exp(a + b × X1,083 – 2 × s)
= Exp(a + b × 1,574 – 2 × s)
= Exp(-7.6416 + 0.0081 × 1,574 – 2 × 0.0328)
= Exp(5.0688)
= $158.99
December 10, 2025 calculations
Top border of price channel:
Exp(Y1,098)
= Exp(a + b × X1,098 + 2 × s)
= Exp(a + b × 1,596 + 2 × s)
= Exp(-7.6416 + 0.0081 × 1,596 + 2 × 0.0328)
= Exp(5.3785)
= $216.70
Bottom border of price channel:
Exp(Y1,098)
= Exp(a + b × X1,098 – 2 × s)
= Exp(a + b × 1,596 – 2 × s)
= Exp(-7.6416 + 0.0081 × 1,596 – 2 × 0.0328)
= Exp(5.2474)
= $190.07
Description
- The secondary trend is increasing.
- The growth rate of the secondary trend is 1,834.95% per annum.
- DUOL price at the close of December 10, 2025 was inside the secondary price channel.