Module 03 · AAPL stochastic paths

Apple as a process, not a point.

Geometric Brownian motion, calibrated on eight Apple annual log-returns, with σ blended against live realized vol. S0 is the last print.

Drift μ

28.3%

Annual log-return mean

Volatility σ

27.0%

blend · annual μ + live realized σ

S0

$336.64

Live tape

Paths

10,000

Stochastic paths

AAPL GBM fan — five years of Wiener noise

NowY1Y2Y3Y4Y5$3,223.12$256.45
Median $1,140.76 IQR 83.2% 5–95

GBM statistics

MetricYear 1Year 3Year 5
Mean$446.67$785.55$1,370.63
Median$430.10$707.75$1,140.76
P5$278.75$327.43$433.52
P95$672.67$1,527.48$3,069.64
P(> $300)91.3%96.5%98.7%
P(> $400)60.6%88.6%96.4%
P(< $150)0.0%0.0%0.1%

GBM finish table

AAPL finish-position probabilities

Each cell is the share of simulated paths that finish a given year inside that price band.

Horizon$50–150$150–250$250–350$350–450$450–650$650–∞
Year 1
Year 2
Year 3
Year 4
Year 5

Jump-diffusion

AAPL Merton jumps · λ = 0.3 / yr, mean jump −5%

NowY1Y2Y3Y4Y5$3,352.38$248.28
Median $1,136.61 IQR 87.2% 5–95

Median comparison

Jump-diffusion versus GBM (median path)

NowY1Y2Y3Y4Y5$1209

How to read this

GBM assumes log-returns are well-behaved. Jump-diffusion adds Poisson shocks — the model’s way of admitting a regulation case, a demand air-pocket, a China weekend. The medians stay close. The fifth percentile does not. That gap is the point. Drift is the eight-year 10-K mean; volatility is blended with whatever the live session has already printed.