title: The Yahoo Finance S&P500 data (^GSPC) reaches back to 1950, why can I only download data from 1970 onwards?
body: <pre><code>import pandas_datareader.data as web
  
  df = web.DataReader('^GSPC', 'yahoo', start='1950-01-03', end='2017-09-14')
  </code></pre>
  
  <p>If I go on the Yahoo Finance website I can manually download data from 1950,  so why can't I do that using pandas datareader? I mean I got the data already, just curious about why it didn't work.</p>
  
  <p>Edit: I get this error:</p>
  
  <pre><code>Traceback (most recent call last):
    File "C:/Users/x/PycharmProjects/Programming for Finance/getsp.py", line 7, in &lt;module&gt;
      df = web.DataReader('^GSPC', 'yahoo', start='1950-01-03', end='2017-09-14')
    File "C:\Users\x\AppData\Local\Programs\Python\Python36\lib\site-packages\pandas_datareader\data.py", line 121, in DataReader
      session=session).read()
    File "C:\Users\x\AppData\Local\Programs\Python\Python36\lib\site-packages\pandas_datareader\yahoo\daily.py", line 115, in read
      df = super(YahooDailyReader, self).read()
    File "C:\Users\x\AppData\Local\Programs\Python\Python36\lib\site-packages\pandas_datareader\base.py", line 181, in read
      params=self._get_params(self.symbols))
    File "C:\Users\x\AppData\Local\Programs\Python\Python36\lib\site-packages\pandas_datareader\yahoo\daily.py", line 99, in _get_params
      unix_start = int(time.mktime(self.start.timetuple()))
  OverflowError: mktime argument out of range
  </code></pre>