估值72法则

\[1+100\% = 1\times (1 + r\%)^n \to n \approx \frac{72}{r}\]

r <- seq(0.001,0.500,by = .001)
yr_actual <- log(2)/log(1+r)
yr_pred <- 72/(r*100)
yr_data <- data_frame(
  r = r,
  yr_actual = yr_actual,
  yr_pred  = yr_pred
) %>%
  mutate(yr_delta = yr_actual-yr_pred)
yr_data %>% 
  gather(key,value,yr_actual:yr_delta) %>%
  ggplot(aes(x = r, y = value, col = key)) +
    geom_line() +
    scale_y_log10()

yr_data %>% 
  mutate(leq0 = yr_delta > 0) %>% 
  ggplot(aes(x = leq0)) +
    geom_bar(aes(y = ..count..))