title: How to calculate stock pullback
body: <p>I am trying to calculate the pullback (percentage change) off of its high. Not necessarily change from high to today, but percentage change from high to the lowest point after that high. </p>
  
  <p>Where I am drawing a blank, is I don't know where to begin with finding the lowest point in the stock <strong>after</strong> the high for the stock. I can find the high for each stock, but how do I trim that column so that it only has the stock prices <strong>after</strong> that high?</p>
  
  <pre><code>import numpy as np
  import pandas as pd
  import datetime as dt
  import pandas.io.data as web
  
  stocks = ['AAPL', 'NFLX', 'MSFT', 'MCD', 'DIS']
  start = dt.datetime(2015, 1, 1)
  end = dt.datetime.today()
  
  df = web.DataReader(stocks, 'yahoo', start, end)
  df = df['Close']
  dfMax = df.max()
  </code></pre>
  
  <p>From here, I have 5 columns, one column for each stock, and the subsequent prices on each day. I am stumped...</p>