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 November 19, 2025 was $174.48 and was lower than the bottom border of the primary price channel by $6.99 (3.85%).
- The secondary trend is decreasing.
- The decline rate of the secondary trend is 99.96% per annum.
- DUOL price at the close of November 19, 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 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 November 19, 2025 was $174.48 and was lower than the bottom border of the primary price channel by $6.99 (3.85%).
Secondary Trend
Start date: October 15, 2025
End date: November 19, 2025
a = 38.9842
b = -0.0215
s = 0.0689
Annual growth rate:
Exp(365 × b) – 1
= Exp(365 × -0.0215) – 1
= -99.96%
Price channel spread:
Exp(4 × s) – 1
= Exp(4 × 0.0689) – 1
= 31.74%
October 15, 2025 calculations
Top border of price channel:
Exp(Y1,059)
= Exp(a + b × X1,059 + 2 × s)
= Exp(a + b × 1,540 + 2 × s)
= Exp(38.9842 + -0.0215 × 1,540 + 2 × 0.0689)
= Exp(6.0267)
= $414.36
Bottom border of price channel:
Exp(Y1,059)
= Exp(a + b × X1,059 – 2 × s)
= Exp(a + b × 1,540 – 2 × s)
= Exp(38.9842 + -0.0215 × 1,540 – 2 × 0.0689)
= Exp(5.7511)
= $314.53
November 19, 2025 calculations
Top border of price channel:
Exp(Y1,084)
= Exp(a + b × X1,084 + 2 × s)
= Exp(a + b × 1,575 + 2 × s)
= Exp(38.9842 + -0.0215 × 1,575 + 2 × 0.0689)
= Exp(5.2746)
= $195.31
Bottom border of price channel:
Exp(Y1,084)
= Exp(a + b × X1,084 – 2 × s)
= Exp(a + b × 1,575 – 2 × s)
= Exp(38.9842 + -0.0215 × 1,575 – 2 × 0.0689)
= Exp(4.9989)
= $148.25
Description
- The secondary trend is decreasing.
- The decline rate of the secondary trend is 99.96% per annum.
- DUOL price at the close of November 19, 2025 was inside the secondary price channel.