XIV data difference

There is a large difference in the XIV data between Q and other source..
Why? In the backtest the diff %.
..the "Open" difference is enourmous

6
Backtest from to with initial capital
Total Returns
--
Alpha
--
Beta
--
Sharpe
--
Sortino
--
Max Drawdown
--
Benchmark Returns
--
Volatility
--
 Returns 1 Month 3 Month 6 Month 12 Month
 Alpha 1 Month 3 Month 6 Month 12 Month
 Beta 1 Month 3 Month 6 Month 12 Month
 Sharpe 1 Month 3 Month 6 Month 12 Month
 Sortino 1 Month 3 Month 6 Month 12 Month
 Volatility 1 Month 3 Month 6 Month 12 Month
 Max Drawdown 1 Month 3 Month 6 Month 12 Month
xivurl = 'http://ichart.finance.yahoo.com/table.csv?s=XIV&d=31&e=12&f=2039&g=d&a=3&b=7&c=1902&ignore=.csv'

def initialize(context):

context.xiv = sid(40516)
fetch_csv(xivurl, symbol='Xiv', skiprows=0, date_column='Date', date_format='%Y-%m-%d')
schedule_function(analysis, date_rules.every_day(), time_rules.market_close(hours = 0, minutes = 1))

def analysis(context, data):

xiv_op_q = data.current(context.xiv, 'open')
xiv_cl_q = data.current(context.xiv, 'close')
xiv_op_y = data.current('Xiv', 'Open')
xiv_cl_y = data.current('Xiv', 'Close')
xiv_op_delta = 100*(xiv_op_q/xiv_op_y-1)
xiv_cl_delta = 100*(xiv_cl_q/xiv_cl_y-1)
#record(XIV_op_Q = xiv_op_q)
#record(XIV_op_Y = xiv_op_y)
#record(XIV_cl_Q = xiv_cl_q)
#record(XIV_cl_Y = xiv_cl_y)
record(XIV_op_Delta = xiv_op_delta)
record(XIV_cl_Delta = xiv_cl_delta)


There was a runtime error.
2 responses

Y, the 9/9/16 open data seems wrong on all the stocks I tried. It seems a lot closer to the close than the open.

Wasn't there something in the documentation about the open being unusable? I don't see it there now.

Probably because data.current is suitable for live/current data; using data.history all is fine, both Open and Close price are correct.
But, still small difference (0,2%) in the closing price between provider (Q, Y, G) still exist. Booohhh????!!! ???